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Solution
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Q.1 Correct
Q.1 In-correct
Q.1 Unattempt

A series LCR circuit is connected to an alternating source of emf E. The current amplitude at resonant frequency is $I_0$. If the value of resistance R becomes twice of its initial value then amplitude of current at resonance will be



JEE Main 2025 (Online) 22nd January Evening Shift

A series LCR circuit is connected to an alternating source of emf E. The current amplitude at resonant frequency is $I_0$. If the value of resistance R becomes twice of its initial value then amplitude of current at resonance will be



JEE Main 2025 (Online) 22nd January Evening Shift
Q.2 Correct
Q.2 In-correct
Q.2 Unattempt

An alternating current is given by $\mathrm{I}=\mathrm{I}_{\mathrm{A}} \sin \omega \mathrm{t}+\mathrm{I}_{\mathrm{B}} \cos \omega \mathrm{t}$. The r.m.s current will be



JEE Main 2025 (Online) 24th January Morning Shift

An alternating current is given by $\mathrm{I}=\mathrm{I}_{\mathrm{A}} \sin \omega \mathrm{t}+\mathrm{I}_{\mathrm{B}} \cos \omega \mathrm{t}$. The r.m.s current will be



JEE Main 2025 (Online) 24th January Morning Shift
Q.3 Correct
Q.3 In-correct
Q.3 Unattempt
An electric bulb rated as $100 \mathrm{~W}-220 \mathrm{~V}$ is connected to an ac source of rms voltage 220 V. The peak value of current through the bulb is :

JEE Main 2025 (Online) 3rd April Evening Shift
An electric bulb rated as $100 \mathrm{~W}-220 \mathrm{~V}$ is connected to an ac source of rms voltage 220 V. The peak value of current through the bulb is :

JEE Main 2025 (Online) 3rd April Evening Shift
Q.4 Correct
Q.4 In-correct
Q.4 Unattempt

An alternating current is represented by the equation,$i=100 \sqrt{2} \sin (100 \pi t)$ ampere. The RMS value of current and the frequency of the given alternating current are



JEE Main 2025 (Online) 4th April Morning Shift

An alternating current is represented by the equation,$i=100 \sqrt{2} \sin (100 \pi t)$ ampere. The RMS value of current and the frequency of the given alternating current are



JEE Main 2025 (Online) 4th April Morning Shift
Q.5 Correct
Q.5 In-correct
Q.5 Unattempt

An ac current is represented as

$$i=5 \sqrt{2}+10 \cos \left(650 \pi t+\frac{\pi}{6}\right) A m p$$

The r.m.s value of the current is



JEE Main 2025 (Online) 7th April Morning Shift

An ac current is represented as

$$i=5 \sqrt{2}+10 \cos \left(650 \pi t+\frac{\pi}{6}\right) A m p$$

The r.m.s value of the current is



JEE Main 2025 (Online) 7th April Morning Shift
Q.6 Correct
Q.6 In-correct
Q.6 Unattempt

In a series LCR circuit, a resistor of $300 \Omega$, a capacitor of 25 nF and an inductor of 100 mH are used. For maximum current in the circuit, the angular frequency of the ac source is _________ $\times 10^4$ radians $\mathrm{s}^{-1}$



JEE Main 2025 (Online) 23rd January Evening Shift

In a series LCR circuit, a resistor of $300 \Omega$, a capacitor of 25 nF and an inductor of 100 mH are used. For maximum current in the circuit, the angular frequency of the ac source is _________ $\times 10^4$ radians $\mathrm{s}^{-1}$



JEE Main 2025 (Online) 23rd January Evening Shift
Q.7 Correct
Q.7 In-correct
Q.7 Unattempt

An inductor of self inductance 1 H is connected in series with a resistor of $100 \pi$ ohm and an ac supply of $100 \pi$ volt, 50 Hz . Maximum current flowing in the circuit is _________ A.



JEE Main 2025 (Online) 4th April Evening Shift

An inductor of self inductance 1 H is connected in series with a resistor of $100 \pi$ ohm and an ac supply of $100 \pi$ volt, 50 Hz . Maximum current flowing in the circuit is _________ A.



JEE Main 2025 (Online) 4th April Evening Shift
Q.8 Correct
Q.8 In-correct
Q.8 Unattempt

For ac circuit shown in figure, $\mathrm{R}=100 \mathrm{k} \Omega$ and $\mathrm{C}=100 \mathrm{pF}$ and the phase difference between $\mathrm{V}_{\text {in }}$ and $\left(\mathrm{V}_{\mathrm{B}}-\mathrm{V}_{\mathrm{A}}\right)$ is $90^{\circ}$. The input signal frequency is $10^x \mathrm{rad} / \mathrm{sec}$, where ' $x$ ' is __________ .

JEE Main 2025 (Online) 7th April Morning Shift Physics - Alternating Current Question 5 English



JEE Main 2025 (Online) 7th April Morning Shift

For ac circuit shown in figure, $\mathrm{R}=100 \mathrm{k} \Omega$ and $\mathrm{C}=100 \mathrm{pF}$ and the phase difference between $\mathrm{V}_{\text {in }}$ and $\left(\mathrm{V}_{\mathrm{B}}-\mathrm{V}_{\mathrm{A}}\right)$ is $90^{\circ}$. The input signal frequency is $10^x \mathrm{rad} / \mathrm{sec}$, where ' $x$ ' is __________ .

JEE Main 2025 (Online) 7th April Morning Shift Physics - Alternating Current Question 5 English



JEE Main 2025 (Online) 7th April Morning Shift
Q.9 Correct
Q.9 In-correct
Q.9 Unattempt
An inductor of reactance $100 \Omega$, a capacitor of reactance $50 \Omega$, and a resistor of resistance $50 \Omega$ are connected in series with an AC source of $10 \mathrm{~V}, 50 \mathrm{~Hz}$. Average power dissipated by the circuit is ___________ W.

JEE Main 2025 (Online) 7th April Evening Shift
An inductor of reactance $100 \Omega$, a capacitor of reactance $50 \Omega$, and a resistor of resistance $50 \Omega$ are connected in series with an AC source of $10 \mathrm{~V}, 50 \mathrm{~Hz}$. Average power dissipated by the circuit is ___________ W.

JEE Main 2025 (Online) 7th April Evening Shift
Q.10 Correct
Q.10 In-correct
Q.10 Unattempt

Primary side of a transformer is connected to 230 V, 50Hz supply. Turns ratio of primary to secondary winding is 10:1. Load resistance connected to secondary side is 46Ω. The power consumed in it is :

[27-Jan-2024 Shift 2]

Primary side of a transformer is connected to 230 V, 50Hz supply. Turns ratio of primary to secondary winding is 10:1. Load resistance connected to secondary side is 46Ω. The power consumed in it is :

[27-Jan-2024 Shift 2]
Q.11 Correct
Q.11 In-correct
Q.11 Unattempt

A series LCR circuit with L = 100/π mH, C = 10-3/π F and R = 10Ω, is connected across an ac source of 220V, 50Hz supply. The power factor of the circuit would be___

[27-Jan-2024 Shift 2]

A series LCR circuit with L = 100/π mH, C = 10-3/π F and R = 10Ω, is connected across an ac source of 220V, 50Hz supply. The power factor of the circuit would be___

[27-Jan-2024 Shift 2]
Q.12 Correct
Q.12 In-correct
Q.12 Unattempt

In the given figure, the charge stored in 6µF capacitor, when points A and B are joined by a connecting wire is ____ µC.

[29-Jan-2024 Shift 2]

In the given figure, the charge stored in 6µF capacitor, when points A and B are joined by a connecting wire is ____ µC.

[29-Jan-2024 Shift 2]
Q.13 Correct
Q.13 In-correct
Q.13 Unattempt

Primary coil of a transformer is connected to 220V ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistance shown in shown in figure. The output voltage (V0) is :

[30-Jan-2024 Shift 1]

Primary coil of a transformer is connected to 220V ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistance shown in shown in figure. The output voltage (V0) is :

[30-Jan-2024 Shift 1]
Q.14 Correct
Q.14 In-correct
Q.14 Unattempt

A series L,R circuit connected with an ac source E = (25sin 1000t)V has a power factor of 1/√2. If the source of emf is changed to E=(20sin2000 t)V, the new power factor of the circuit will be :

[30-Jan-2024 Shift 1]

A series L,R circuit connected with an ac source E = (25sin 1000t)V has a power factor of 1/√2. If the source of emf is changed to E=(20sin2000 t)V, the new power factor of the circuit will be :

[30-Jan-2024 Shift 1]
Q.15 Correct
Q.15 In-correct
Q.15 Unattempt

An alternating voltage V(t) = 220sin 100πt volt is applied to a purely resistive load of 50Ω. The time taken for the current to rise from half of the peak value to the peak value is:

[30-Jan-2024 Shift 2]

An alternating voltage V(t) = 220sin 100πt volt is applied to a purely resistive load of 50Ω. The time taken for the current to rise from half of the peak value to the peak value is:

[30-Jan-2024 Shift 2]
Q.16 Correct
Q.16 In-correct
Q.16 Unattempt

A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230V by the transformer. The current in the primary of the transformer is 5A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is_____A.

[30-Jan-2024 Shift 2]

A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230V by the transformer. The current in the primary of the transformer is 5A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is_____A.

[30-Jan-2024 Shift 2]
Q.17 Correct
Q.17 In-correct
Q.17 Unattempt

An AC voltage V = 20sin 200πt is applied to a series LCR circuit which drives a current I = 10sin (200πt + π/3). The average power dissipated is:

[31-Jan-2024 Shift 2]

An AC voltage V = 20sin 200πt is applied to a series LCR circuit which drives a current I = 10sin (200πt + π/3). The average power dissipated is:

[31-Jan-2024 Shift 2]
Q.18 Correct
Q.18 In-correct
Q.18 Unattempt

A parallel plate capacitor has a capacitance C = 200pF. It is connected to 230V ac supply with an angular frequency 300rad∕ s. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are :

[1-Feb-2024 Shift 1]

A parallel plate capacitor has a capacitance C = 200pF. It is connected to 230V ac supply with an angular frequency 300rad∕ s. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are :

[1-Feb-2024 Shift 1]
Q.19 Correct
Q.19 In-correct
Q.19 Unattempt

In series LCR circuit, the capacitance is changed from C to 4C. To keep the resonance frequency unchanged, the new inductance should be :

[1-Feb-2024 Shift 1]

In series LCR circuit, the capacitance is changed from C to 4C. To keep the resonance frequency unchanged, the new inductance should be :

[1-Feb-2024 Shift 1]
Q.20 Correct
Q.20 In-correct
Q.20 Unattempt

A transformer has an efficiency of 80% and works at 10V and 4kW. If the secondary voltage is 240V, then the current in the secondary coil is :

[1-Feb-2024 Shift 2]

A transformer has an efficiency of 80% and works at 10V and 4kW. If the secondary voltage is 240V, then the current in the secondary coil is :

[1-Feb-2024 Shift 2]
Q.21 Correct
Q.21 In-correct
Q.21 Unattempt
In the circuit shown in the figure, the ratio of the quality factor and the band width is____s.

[24-Jan-2023 Shift 1]
In the circuit shown in the figure, the ratio of the quality factor and the band width is____s.

[24-Jan-2023 Shift 1]
Q.22 Correct
Q.22 In-correct
Q.22 Unattempt
Three identical resistors with resistance R=12Ω and two identical inductors with sell inductance L=5‌mH are connected to an ideal battery with emf of 12V as shown in figure. The current through the battery long after the switch has been closed will be___A.

[24-Jan-2023 Shift 2]
Three identical resistors with resistance R=12Ω and two identical inductors with sell inductance L=5‌mH are connected to an ideal battery with emf of 12V as shown in figure. The current through the battery long after the switch has been closed will be___A.

[24-Jan-2023 Shift 2]
Q.23 Correct
Q.23 In-correct
Q.23 Unattempt
In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes x times its initial resonant frequency ω0. The value of x is:
[25-Jan-2023 Shift 1]
In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes x times its initial resonant frequency ω0. The value of x is:
[25-Jan-2023 Shift 1]
Q.24 Correct
Q.24 In-correct
Q.24 Unattempt
An LCR series circuit of capacitance 62.5‌nF and resistance of 50Ω. is connected to an A.C. source of frequency 2.0‌kHz. For maximum value of amplitude of current in circuit, the value of inductance is ________ mH.
(take π2=10 )
[25-Jan-2023 Shift 1]
An LCR series circuit of capacitance 62.5‌nF and resistance of 50Ω. is connected to an A.C. source of frequency 2.0‌kHz. For maximum value of amplitude of current in circuit, the value of inductance is ________ mH.
(take π2=10 )
[25-Jan-2023 Shift 1]
Q.25 Correct
Q.25 In-correct
Q.25 Unattempt
A series LCR circuit is connected to an AC source of 220V,50‌Hz. The circuit contains a resistance R=80Ω, an inductor of inductive reactance XL=70Ω, and a capacitor of capacitive reactance XC=130Ω. The power factor of circuit is ‌
X
10
. The value of x is :
[25-Jan-2023 Shift 2]
A series LCR circuit is connected to an AC source of 220V,50‌Hz. The circuit contains a resistance R=80Ω, an inductor of inductive reactance XL=70Ω, and a capacitor of capacitive reactance XC=130Ω. The power factor of circuit is ‌
X
10
. The value of x is :
[25-Jan-2023 Shift 2]
Q.26 Correct
Q.26 In-correct
Q.26 Unattempt
Find the mutual inductance in the arrangement, when a small circular loop of wire of radius ' R ' is placed inside a large square loop of wire of side L (L≫R). The loops are coplanar and their centres coincide :

[29-Jan-2023 Shift 1]
Find the mutual inductance in the arrangement, when a small circular loop of wire of radius ' R ' is placed inside a large square loop of wire of side L (L≫R). The loops are coplanar and their centres coincide :

[29-Jan-2023 Shift 1]
Q.27 Correct
Q.27 In-correct
Q.27 Unattempt
For the given figures, choose the correct options:

[29-Jan-2023 Shift 2]
For the given figures, choose the correct options:

[29-Jan-2023 Shift 2]
Q.28 Correct
Q.28 In-correct
Q.28 Unattempt
An inductor of inductance 2µH is connected in series with a resistance, a variable capacitor and an AC source of frequency 7‌kHz. The value of capacitance for which maximum current is drawn into the circuit is ‌
1
x
F, where the value of x is _______.
(. Take π=‌
22
7
)
[29-Jan-2023 Shift 2]
An inductor of inductance 2µH is connected in series with a resistance, a variable capacitor and an AC source of frequency 7‌kHz. The value of capacitance for which maximum current is drawn into the circuit is ‌
1
x
F, where the value of x is _______.
(. Take π=‌
22
7
)
[29-Jan-2023 Shift 2]
Q.29 Correct
Q.29 In-correct
Q.29 Unattempt
A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of 120V and 80V respectively. The amplitude of each sideband is :
[30-Jan-2023 Shift 1]
A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of 120V and 80V respectively. The amplitude of each sideband is :
[30-Jan-2023 Shift 1]
Q.30 Correct
Q.30 In-correct
Q.30 Unattempt
In a series LR circuit with XL=R. power factor is P1. If a capacitor of capacitance C with XC=XL is added to the circuit the power factor becomes P2. The ratio of P1 to P2 will be :
[30-Jan-2023 Shift 1]
In a series LR circuit with XL=R. power factor is P1. If a capacitor of capacitance C with XC=XL is added to the circuit the power factor becomes P2. The ratio of P1 to P2 will be :
[30-Jan-2023 Shift 1]
Q.31 Correct
Q.31 In-correct
Q.31 Unattempt
In the given circuit, rms value of current (Irms) through the resistor R is :

[30-Jan-2023 Shift 2]
In the given circuit, rms value of current (Irms) through the resistor R is :

[30-Jan-2023 Shift 2]
Q.32 Correct
Q.32 In-correct
Q.32 Unattempt
In an ac generator, a rectangular coil of 100 turns each having area 14×10−2m2 is rotated at 360‌rev∕min about an axis perpendicular to a uniform magnetic field of magnitude 3.0T. The maximum value of the emf produced will be V _______.(. Take π=‌
22
7
)
[30-Jan-2023 Shift 2]
In an ac generator, a rectangular coil of 100 turns each having area 14×10−2m2 is rotated at 360‌rev∕min about an axis perpendicular to a uniform magnetic field of magnitude 3.0T. The maximum value of the emf produced will be V _______.(. Take π=‌
22
7
)
[30-Jan-2023 Shift 2]
Q.33 Correct
Q.33 In-correct
Q.33 Unattempt
An alternating voltage source V=260sin‌(628t) is connected across a pure inductor of 5‌mH. Inductive reactance in the circuit is:
[31-Jan-2023 Shift 2]
An alternating voltage source V=260sin‌(628t) is connected across a pure inductor of 5‌mH. Inductive reactance in the circuit is:
[31-Jan-2023 Shift 2]
Q.34 Correct
Q.34 In-correct
Q.34 Unattempt
A series LCR circuit consists of R=80ΩXL=100Ω, and XC=40Ω The input voltage is 2500‌cos(100πt) V. The amplitude of current, in the circuit, is ________ A.
[31-Jan-2023 Shift 2]
A series LCR circuit consists of R=80ΩXL=100Ω, and XC=40Ω The input voltage is 2500‌cos(100πt) V. The amplitude of current, in the circuit, is ________ A.
[31-Jan-2023 Shift 2]
Q.35 Correct
Q.35 In-correct
Q.35 Unattempt
Match the List I with List II

Choose the correct answer from the options given below:
[1-Feb-2023 Shift 1]
Match the List I with List II

Choose the correct answer from the options given below:
[1-Feb-2023 Shift 1]
Q.36 Correct
Q.36 In-correct
Q.36 Unattempt
A series LCR circuit is connected to an ac source of 220V,50‌Hz. The circuit contain a resistance R=100Ω and an inductor of inductive reactance XL=79.6Ω. The capacitance of the capacitor needed to maximize the average rate at which energy is supplied will be _______ µF.
[1-Feb-2023 Shift 1]
A series LCR circuit is connected to an ac source of 220V,50‌Hz. The circuit contain a resistance R=100Ω and an inductor of inductive reactance XL=79.6Ω. The capacitance of the capacitor needed to maximize the average rate at which energy is supplied will be _______ µF.
[1-Feb-2023 Shift 1]
Q.37 Correct
Q.37 In-correct
Q.37 Unattempt
An ideal transformer with purely resistive load operates at 12‌kV on the primary side. It supplies electrical energy to a number of nearby houses at 120V. The average rate of energy consumption in the houses served by the transformer is 60‌kW. The value of resistive load (Rs) required in the secondary circuit will be mΩ.
[6-Apr-2023 shift 1]
An ideal transformer with purely resistive load operates at 12‌kV on the primary side. It supplies electrical energy to a number of nearby houses at 120V. The average rate of energy consumption in the houses served by the transformer is 60‌kW. The value of resistive load (Rs) required in the secondary circuit will be mΩ.
[6-Apr-2023 shift 1]
Q.38 Correct
Q.38 In-correct
Q.38 Unattempt
A capacitor of capacitance 150.0µF is connected to an alternating source of emf given by E=36sin‌(120πt)V. The maximum value of current in the circuit is approximatively equal to :
[6-Apr-2023 shift 2]
A capacitor of capacitance 150.0µF is connected to an alternating source of emf given by E=36sin‌(120πt)V. The maximum value of current in the circuit is approximatively equal to :
[6-Apr-2023 shift 2]
Q.39 Correct
Q.39 In-correct
Q.39 Unattempt
An oscillating LC circuit consists of a 75‌mH inductor and a 1.2µF capacitor. If the maximum charge to the capacitor is 2.7µC. The maximum current in the circuit will be ________ mA.
[8-Apr-2023 shift 1]
An oscillating LC circuit consists of a 75‌mH inductor and a 1.2µF capacitor. If the maximum charge to the capacitor is 2.7µC. The maximum current in the circuit will be ________ mA.
[8-Apr-2023 shift 1]
Q.40 Correct
Q.40 In-correct
Q.40 Unattempt
A series combination of resistor of resistance 100Ω, inductor of inductance 1H and capacitor of capacitance 6.25µF is connected to an ac source. The quality factor of the circuit will be _______.
[8-Apr-2023 shift 2]
A series combination of resistor of resistance 100Ω, inductor of inductance 1H and capacitor of capacitance 6.25µF is connected to an ac source. The quality factor of the circuit will be _______.
[8-Apr-2023 shift 2]
Q.41 Correct
Q.41 In-correct
Q.41 Unattempt
Given below are two statements:
Statement I : Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an AC source, when resonance occurs
Statement II : Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage.
In the light of the above statements, choose the correct answer from the options given below :
[10-Apr-2023 shift 1]
Given below are two statements:
Statement I : Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an AC source, when resonance occurs
Statement II : Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage.
In the light of the above statements, choose the correct answer from the options given below :
[10-Apr-2023 shift 1]
Q.42 Correct
Q.42 In-correct
Q.42 Unattempt
As per the given graph, choose the correct representation for curve A and curve B.
{. Where XC= reactance of pure capacitive circuit connected with A.C. source
XL= reactance of pure inductive circuit connected with A.C. source
R= impedance of pure resistive circuit connected with A.C. source.
Z= impedance of the LCR series circuit
[11-Apr-2023 shift 1]

As per the given graph, choose the correct representation for curve A and curve B.
{. Where XC= reactance of pure capacitive circuit connected with A.C. source
XL= reactance of pure inductive circuit connected with A.C. source
R= impedance of pure resistive circuit connected with A.C. source.
Z= impedance of the LCR series circuit
[11-Apr-2023 shift 1]
Q.43 Correct
Q.43 In-correct
Q.43 Unattempt
Given below are two statements:
Statements I : When the frequency of an a.c source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases
Statements II : In a series LCR circuit, the value of power factor at resonance is one.
In the light of given statements, choose the most appropriate answer from the options given below.
[12-Apr-2023 shift 1]
Given below are two statements:
Statements I : When the frequency of an a.c source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases
Statements II : In a series LCR circuit, the value of power factor at resonance is one.
In the light of given statements, choose the most appropriate answer from the options given below.
[12-Apr-2023 shift 1]
Q.44 Correct
Q.44 In-correct
Q.44 Unattempt
Given below are two statements :
Statements I : An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor.
Statement II : An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor.
In the light of above statements, choose the correct answer form the options given below :
[13-Apr-2023 shift 2]
Given below are two statements :
Statements I : An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor.
Statement II : An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor.
In the light of above statements, choose the correct answer form the options given below :
[13-Apr-2023 shift 2]
Q.45 Correct
Q.45 In-correct
Q.45 Unattempt
A resistance of 40Ω is connected to a source of alternating current rated 220V,50‌Hz. Find the time taken by the current to change from its maximum value to the rms value :
[24-Jun-2022-Shift-1]
A resistance of 40Ω is connected to a source of alternating current rated 220V,50‌Hz. Find the time taken by the current to change from its maximum value to the rms value :
[24-Jun-2022-Shift-1]
Q.46 Correct
Q.46 In-correct
Q.46 Unattempt
As shown in the figure an inductor of inductance 200‌mH is connected to an AC source of emf 220V and frequency 50‌Hz. The instantaneous voltage of the source is 0V when the peak value of current is ‌
√a
π
A. The value of a is _____

[24-Jun-2022-Shift-1]
As shown in the figure an inductor of inductance 200‌mH is connected to an AC source of emf 220V and frequency 50‌Hz. The instantaneous voltage of the source is 0V when the peak value of current is ‌
√a
π
A. The value of a is _____

[24-Jun-2022-Shift-1]
Q.47 Correct
Q.47 In-correct
Q.47 Unattempt
Given below are two statements:
Statement I: The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an inductor.
Statement II : In ac circuit, the average power delivered by the source never becomes zero.
In the light of the above statements, choose the correct answer from the options given below.
[24-Jun-2022-Shift-2]
Given below are two statements:
Statement I: The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an inductor.
Statement II : In ac circuit, the average power delivered by the source never becomes zero.
In the light of the above statements, choose the correct answer from the options given below.
[24-Jun-2022-Shift-2]
Q.48 Correct
Q.48 In-correct
Q.48 Unattempt
Choose the correct answer from the options given below :

[25-Jun-2022-Shift-1]
Choose the correct answer from the options given below :

[25-Jun-2022-Shift-1]
Q.49 Correct
Q.49 In-correct
Q.49 Unattempt
If wattless current flows in the AC circuit, then the circuit is :
[25-Jun-2022-Shift-1]
If wattless current flows in the AC circuit, then the circuit is :
[25-Jun-2022-Shift-1]
Q.50 Correct
Q.50 In-correct
Q.50 Unattempt
A sinusoidal voltage V(t)=210‌sin‌3000‌t volt is applied to a series LCR circuit in which L=10‌mH,C=25µF and R =100Ω. The phase difference (Φ) between the applied voltage and resultant current will be :
[25-Jun-2022-Shift-2]
A sinusoidal voltage V(t)=210‌sin‌3000‌t volt is applied to a series LCR circuit in which L=10‌mH,C=25µF and R =100Ω. The phase difference (Φ) between the applied voltage and resultant current will be :
[25-Jun-2022-Shift-2]
Q.51 Correct
Q.51 In-correct
Q.51 Unattempt
In a series LCR circuit, the inductance, capacitance and resistance are L=100‌mH,C=100µF and R=10Ω respectively. They are connected to an AC source of voltage 200V and frequency of 50‌Hz. The approximate value of current in the circuit will be A.

[25-Jun-2022-Shift-2]
In a series LCR circuit, the inductance, capacitance and resistance are L=100‌mH,C=100µF and R=10Ω respectively. They are connected to an AC source of voltage 200V and frequency of 50‌Hz. The approximate value of current in the circuit will be A.

[25-Jun-2022-Shift-2]
Q.52 Correct
Q.52 In-correct
Q.52 Unattempt
A 110V,50‌Hz,AC source is connected in the circuit (as shown in figure). The current through the resistance 55Ω, at resonance in the circuit, will be _____A.

[26-Jun-2022-Shift-1]
A 110V,50‌Hz,AC source is connected in the circuit (as shown in figure). The current through the resistance 55Ω, at resonance in the circuit, will be _____A.

[26-Jun-2022-Shift-1]
Q.53 Correct
Q.53 In-correct
Q.53 Unattempt
The current flowing through an ac circuit is given by
I=5‌sin(120πt)‌A
How long will the current take to reach the peak value starting from zero?
[27-Jun-2022-Shift-1]
The current flowing through an ac circuit is given by
I=5‌sin(120πt)‌A
How long will the current take to reach the peak value starting from zero?
[27-Jun-2022-Shift-1]
Q.54 Correct
Q.54 In-correct
Q.54 Unattempt
An AC source is connected to an inductance of 100‌mH, a capacitance of 100µF and a resistance of 120Ω as shown in figure. The time in which the resistance having a thermal capacity 2J∕‌∘C will get heated by 16∘C is______ s.

[28-Jun-2022-Shift-1]
An AC source is connected to an inductance of 100‌mH, a capacitance of 100µF and a resistance of 120Ω as shown in figure. The time in which the resistance having a thermal capacity 2J∕‌∘C will get heated by 16∘C is______ s.

[28-Jun-2022-Shift-1]
Q.55 Correct
Q.55 In-correct
Q.55 Unattempt
A telegraph line of length 100‌km has a capacity of 0.01µF∕km and it carries an alternating current at 0.5‌kilo cycle per second. If minimum impedance is required, then the value of the inductance that needs to be introduced in series is ____mH(if‌π=√10)
[28-Jun-2022-Shift-1]
A telegraph line of length 100‌km has a capacity of 0.01µF∕km and it carries an alternating current at 0.5‌kilo cycle per second. If minimum impedance is required, then the value of the inductance that needs to be introduced in series is ____mH(if‌π=√10)
[28-Jun-2022-Shift-1]
Q.56 Correct
Q.56 In-correct
Q.56 Unattempt
In the given circuit, the magnitude of VL and VC are twice that of VR. Given that f=50‌Hz, the inductance of the coil is ‌
1
Kπ
‌mH. The value of K is____

[28-Jun-2022-Shift-2]
In the given circuit, the magnitude of VL and VC are twice that of VR. Given that f=50‌Hz, the inductance of the coil is ‌
1
Kπ
‌mH. The value of K is____

[28-Jun-2022-Shift-2]
Q.57 Correct
Q.57 In-correct
Q.57 Unattempt
Choose the most appropriate answer from the options given below :
For a series LCR circuit, I vs ω curve is shown :
(a) To the left of ωr, the circuit is mainly capacitive.
(b) To the left of ωr, the circuit is mainly inductive.
(c) At ωr, impedance of the circuit is equal to the resistance of the circuit.
(d) At ωr, impedance of the circuit is 0 .

[29-Jun-2022-Shift-1]
Choose the most appropriate answer from the options given below :
For a series LCR circuit, I vs ω curve is shown :
(a) To the left of ωr, the circuit is mainly capacitive.
(b) To the left of ωr, the circuit is mainly inductive.
(c) At ωr, impedance of the circuit is equal to the resistance of the circuit.
(d) At ωr, impedance of the circuit is 0 .

[29-Jun-2022-Shift-1]
Q.58 Correct
Q.58 In-correct
Q.58 Unattempt
An inductor of 0.5‌mH, a capacitor of 200µF and a resistor of 2Ω are connected in series with a 220V ac source. If the current is in phase with the emf, the frequency of ac source will be ______×102‌Hz
[29-Jun-2022-Shift-2]
An inductor of 0.5‌mH, a capacitor of 200µF and a resistor of 2Ω are connected in series with a 220V ac source. If the current is in phase with the emf, the frequency of ac source will be ______×102‌Hz
[29-Jun-2022-Shift-2]
Q.59 Correct
Q.59 In-correct
Q.59 Unattempt
To increase the resonant frequency in series LCR circuit,
[25-Jul-2022-Shift-1]
To increase the resonant frequency in series LCR circuit,
[25-Jul-2022-Shift-1]
Q.60 Correct
Q.60 In-correct
Q.60 Unattempt
The rms value of conduction current in a parallel plate capacitor is 6.9µA. The capacity of this capacitor, if it is connected to 230V ac supply with an angular frequency of 600rad∕s, will be:
[25-Jul-2022-Shift-1]
The rms value of conduction current in a parallel plate capacitor is 6.9µA. The capacity of this capacitor, if it is connected to 230V ac supply with an angular frequency of 600rad∕s, will be:
[25-Jul-2022-Shift-1]
Q.61 Correct
Q.61 In-correct
Q.61 Unattempt
When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on :
[25-Jul-2022-Shift-2]
When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on :
[25-Jul-2022-Shift-2]
Q.62 Correct
Q.62 In-correct
Q.62 Unattempt
In a series LR circuit XL=R and power factor of the circuit is P1. When capacitor with capacitance C such that XL=XC is put in series, the power factor becomes P2. The ratio ‌
P1
P2
 is:
[26-Jul-2022-Shift-1]
In a series LR circuit XL=R and power factor of the circuit is P1. When capacitor with capacitance C such that XL=XC is put in series, the power factor becomes P2. The ratio ‌
P1
P2
 is:
[26-Jul-2022-Shift-1]
Q.63 Correct
Q.63 In-correct
Q.63 Unattempt
The effective current I in the given circuit at very high frequencies will be A.

[26-Jul-2022-Shift-1]
The effective current I in the given circuit at very high frequencies will be A.

[26-Jul-2022-Shift-1]
Q.64 Correct
Q.64 In-correct
Q.64 Unattempt
To light, a 50W,100V lamp is connected, in series with a capacitor of capacitance ‌
50
π√x
µF, with 200V,50‌Hz‌AC source. The value of x will be _________.
[27-Jul-2022-Shift-1]
To light, a 50W,100V lamp is connected, in series with a capacitor of capacitance ‌
50
π√x
µF, with 200V,50‌Hz‌AC source. The value of x will be _________.
[27-Jul-2022-Shift-1]
Q.65 Correct
Q.65 In-correct
Q.65 Unattempt
A series LCR circuit has L=0.01H,R=10Ω and C=1µF and it is connected to ac voltage of amplitude (Vm)50V. At frequency 60% lower than resonant frequency, the amplitude of current will be approximately :
[27-Jul-2022-Shift-2]
A series LCR circuit has L=0.01H,R=10Ω and C=1µF and it is connected to ac voltage of amplitude (Vm)50V. At frequency 60% lower than resonant frequency, the amplitude of current will be approximately :
[27-Jul-2022-Shift-2]
Q.66 Correct
Q.66 In-correct
Q.66 Unattempt
The equation of current in a purely inductive circuit is 5‌sin(49πt−30∘). If the inductance is 30‌mH then the equation for the voltage across the inductor, will be :
{. Let .π=‌
22
7
}
[28-Jul-2022-Shift-1]
The equation of current in a purely inductive circuit is 5‌sin(49πt−30∘). If the inductance is 30‌mH then the equation for the voltage across the inductor, will be :
{. Let .π=‌
22
7
}
[28-Jul-2022-Shift-1]
Q.67 Correct
Q.67 In-correct
Q.67 Unattempt
The frequencies at which the current amplitude in an LCR series circuit becomes ‌
1
√2
 times its maximum value, are 212‌rad‌s−1 and 232‌rad‌s−1. The value of resistance in the circuit is R=5Ω. The self inductance in the circuit is _______ mH.
[28-Jul-2022-Shift-1]
The frequencies at which the current amplitude in an LCR series circuit becomes ‌
1
√2
 times its maximum value, are 212‌rad‌s−1 and 232‌rad‌s−1. The value of resistance in the circuit is R=5Ω. The self inductance in the circuit is _______ mH.
[28-Jul-2022-Shift-1]
Q.68 Correct
Q.68 In-correct
Q.68 Unattempt
An alternating emf E=440‌sin‌100‌π‌t is applied to a circuit containing an inductance of ‌
√2
π
H. If an a.c. ammeter is connected in the circuit, its reading will be :
[29-Jul-2022-Shift-1]
An alternating emf E=440‌sin‌100‌π‌t is applied to a circuit containing an inductance of ‌
√2
π
H. If an a.c. ammeter is connected in the circuit, its reading will be :
[29-Jul-2022-Shift-1]
Q.69 Correct
Q.69 In-correct
Q.69 Unattempt
A coil of inductance 1H and resistance 100Ω is connected to a battery of 6V. Determine approximately :
(a) The time elapsed before the current acquires half of its steady - state value.
(b) The energy stored in the magnetic field associated with the coil at an instant 15‌ms after the circuit is switched on. (Given ln‌2=0.693,e−3∕2=0.25 )
[29-Jul-2022-Shift-1]
A coil of inductance 1H and resistance 100Ω is connected to a battery of 6V. Determine approximately :
(a) The time elapsed before the current acquires half of its steady - state value.
(b) The energy stored in the magnetic field associated with the coil at an instant 15‌ms after the circuit is switched on. (Given ln‌2=0.693,e−3∕2=0.25 )
[29-Jul-2022-Shift-1]
Q.70 Correct
Q.70 In-correct
Q.70 Unattempt
A circuit element X when connected to an a.c. supply of peak voltage 100V gives a peak current of 5A which is in phase with the voltage. A second element Y when connected to the same a.c. supply also gives the same value of peak current which lags behind the voltage by ‌
π
2
. If X and Y are connected in series to the same supply, what will be the rms value of the current in ampere?
[29-Jul-2022-Shift-2]
A circuit element X when connected to an a.c. supply of peak voltage 100V gives a peak current of 5A which is in phase with the voltage. A second element Y when connected to the same a.c. supply also gives the same value of peak current which lags behind the voltage by ‌
π
2
. If X and Y are connected in series to the same supply, what will be the rms value of the current in ampere?
[29-Jul-2022-Shift-2]
Q.71 Correct
Q.71 In-correct
Q.71 Unattempt
A capacitor of capacitance 500µF is charged completely using a dc supply of 100V. It is now connected to an inductor of inductance 50‌mH to form an LC circuit. The maximum current in LC circuit will be ________ A.
[29-Jul-2022-Shift-2]
A capacitor of capacitance 500µF is charged completely using a dc supply of 100V. It is now connected to an inductor of inductance 50‌mH to form an LC circuit. The maximum current in LC circuit will be ________ A.
[29-Jul-2022-Shift-2]
Q.72 Correct
Q.72 In-correct
Q.72 Unattempt
Find the peak current and resonant frequency of the following circuit (as shown in figure).

[26 Feb 2021 Shift 2]
Find the peak current and resonant frequency of the following circuit (as shown in figure).

[26 Feb 2021 Shift 2]
Q.73 Correct
Q.73 In-correct
Q.73 Unattempt
An alternating current is given by the equation i=i1‌sin‌ω‌t+i2‌cos‌ω‌t. The rms current will be
[26 Feb 2021 Shift 1]
An alternating current is given by the equation i=i1‌sin‌ω‌t+i2‌cos‌ω‌t. The rms current will be
[26 Feb 2021 Shift 1]
Q.74 Correct
Q.74 In-correct
Q.74 Unattempt
In a series L−C−R resonant circuit, the quality factor is measured as 100 . If the inductance is increased by two fold and resistance is decreased by two fold, then the quality factor after this change will be ......... .
[26 Feb 2021 Shift 1]
In a series L−C−R resonant circuit, the quality factor is measured as 100 . If the inductance is increased by two fold and resistance is decreased by two fold, then the quality factor after this change will be ......... .
[26 Feb 2021 Shift 1]
Q.75 Correct
Q.75 In-correct
Q.75 Unattempt
The angular frequency of alternating current in an L-C-R circuit is 100rad∕s. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser.

[25 Feb 2021 Shift 1]
The angular frequency of alternating current in an L-C-R circuit is 100rad∕s. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser.

[25 Feb 2021 Shift 1]
Q.76 Correct
Q.76 In-correct
Q.76 Unattempt
The current (i) at time t=0 and t=∞ respectively for the given circuit is

[25 Feb 2021 Shift 1]
The current (i) at time t=0 and t=∞ respectively for the given circuit is

[25 Feb 2021 Shift 1]
Q.77 Correct
Q.77 In-correct
Q.77 Unattempt
A transmitting station releases waves of wavelength 960m. A capacitor of 2.56µF is used in the resonant circuit. The self-inductance of coil necessary for resonance is ......... ×10−8H.
[25 Feb 2021 Shift 1]
A transmitting station releases waves of wavelength 960m. A capacitor of 2.56µF is used in the resonant circuit. The self-inductance of coil necessary for resonance is ......... ×10−8H.
[25 Feb 2021 Shift 1]
Q.78 Correct
Q.78 In-correct
Q.78 Unattempt
Figure shows a circuit that contains four identical resistors with resistance R=2.0Ω, two identical inductors with inductance L=2.0mH and an ideal battery with electromotive force E=9V. The current i just after the switch S is closed will be

[24 Feb 2021 Shift 2]
Figure shows a circuit that contains four identical resistors with resistance R=2.0Ω, two identical inductors with inductance L=2.0mH and an ideal battery with electromotive force E=9V. The current i just after the switch S is closed will be

[24 Feb 2021 Shift 2]
Q.79 Correct
Q.79 In-correct
Q.79 Unattempt
A resonance circuit having inductance and resistance 2×10−4H and 6.28Ω respectively oscillates at 10MHz frequency. The value of quality factor of this resonator is[π=3.14]
[24feb2021shift1]
A resonance circuit having inductance and resistance 2×10−4H and 6.28Ω respectively oscillates at 10MHz frequency. The value of quality factor of this resonator is[π=3.14]
[24feb2021shift1]
Q.80 Correct
Q.80 In-correct
Q.80 Unattempt
A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220V (A.C.) on standard domestic A.C. supply. The number of turns of secondary coil are 24 , then the number of turns of primary are
[24feb2021shift1]
A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220V (A.C.) on standard domestic A.C. supply. The number of turns of secondary coil are 24 , then the number of turns of primary are
[24feb2021shift1]
Q.81 Correct
Q.81 In-correct
Q.81 Unattempt
In a series L−C−R resonance circuit, if we change the resistance only, from a lower to higher value,
[18 Mar 2021 Shift 1]
In a series L−C−R resonance circuit, if we change the resistance only, from a lower to higher value,
[18 Mar 2021 Shift 1]
Q.82 Correct
Q.82 In-correct
Q.82 Unattempt
An AC source rated 220V,50Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is
[18 Mar 2021 Shift 1]
An AC source rated 220V,50Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is
[18 Mar 2021 Shift 1]
Q.83 Correct
Q.83 In-correct
Q.83 Unattempt
What happens to the inductive reactance and the current in a purely inductive circuit, if the frequency is halved ?
[17 Mar 2021 Shift 2]
What happens to the inductive reactance and the current in a purely inductive circuit, if the frequency is halved ?
[17 Mar 2021 Shift 2]
Q.84 Correct
Q.84 In-correct
Q.84 Unattempt
Match List-I with List-II

Choose the most appropriate answer from the options given below.
[17 Mar 2021 Shift 2]
Match List-I with List-II

Choose the most appropriate answer from the options given below.
[17 Mar 2021 Shift 2]
Q.85 Correct
Q.85 In-correct
Q.85 Unattempt
An AC current is given by I=I1‌sin‌ω‌t+I2‌cos‌ω‌t. A hot wire ammeter will give a reading
[17 Mar 2021 Shift 1]
An AC current is given by I=I1‌sin‌ω‌t+I2‌cos‌ω‌t. A hot wire ammeter will give a reading
[17 Mar 2021 Shift 1]
Q.86 Correct
Q.86 In-correct
Q.86 Unattempt
A sinusoidal voltage of peak value 250V is applied to a series L−C−R circuit, in which R=8Ω,L=24mH and C=60µF. The value of power dissipated at resonant condition is xkW. The value of x to the nearest integer is
[16 Mar 2021 Shift 1]
A sinusoidal voltage of peak value 250V is applied to a series L−C−R circuit, in which R=8Ω,L=24mH and C=60µF. The value of power dissipated at resonant condition is xkW. The value of x to the nearest integer is
[16 Mar 2021 Shift 1]
Q.87 Correct
Q.87 In-correct
Q.87 Unattempt
An R−C circuit as shown in the figure is driven by an AC source generating a square wav The output wave pattern monitored by CRO would look close to

[16 Mar 2021 Shift 1]
An R−C circuit as shown in the figure is driven by an AC source generating a square wav The output wave pattern monitored by CRO would look close to

[16 Mar 2021 Shift 1]
Q.88 Correct
Q.88 In-correct
Q.88 Unattempt
For the given circuit, comment on the type of transformer used.

[16 Mar 2021 Shift 2]
For the given circuit, comment on the type of transformer used.

[16 Mar 2021 Shift 2]
Q.89 Correct
Q.89 In-correct
Q.89 Unattempt
A 100 Ω resistance, a 0.1 µF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will occur. Given that the resonant frequency is 60 Hz.
[27 Jul 2021 Shift 2]
A 100 Ω resistance, a 0.1 µF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will occur. Given that the resonant frequency is 60 Hz.
[27 Jul 2021 Shift 2]
Q.90 Correct
Q.90 In-correct
Q.90 Unattempt
A 0.07H inductor and a 12Ω resistor are connected in series to a 220V,50Hz ac source. The approximate current in the circuit and the phase angle between current and source voltage are respectively. [Take π as
22
7
 ]
[27 Jul 2021 Shift 1]
A 0.07H inductor and a 12Ω resistor are connected in series to a 220V,50Hz ac source. The approximate current in the circuit and the phase angle between current and source voltage are respectively. [Take π as
22
7
 ]
[27 Jul 2021 Shift 1]
Q.91 Correct
Q.91 In-correct
Q.91 Unattempt
Two circuits are shown in the figure (a) & (b). At a frequency of _______ rad/s the average power dissipated in one cycle will be same in both the circuits.

[25 Jul 2021 Shift 2]
Two circuits are shown in the figure (a) & (b). At a frequency of _______ rad/s the average power dissipated in one cycle will be same in both the circuits.

[25 Jul 2021 Shift 2]
Q.92 Correct
Q.92 In-correct
Q.92 Unattempt
In a circuit consisting of a capacitance and a generator with alternating emf Eg=Eg0‌sin‌ω‌t,VCand IC are the voltage and current. Correct phasor diagram for such circuit is :

[22 Jul 2021 Shift 2]
In a circuit consisting of a capacitance and a generator with alternating emf Eg=Eg0‌sin‌ω‌t,VCand IC are the voltage and current. Correct phasor diagram for such circuit is :

[22 Jul 2021 Shift 2]
Q.93 Correct
Q.93 In-correct
Q.93 Unattempt
Match List-I with List-II :

Choose the correct answer from the options given below :
[22 Jul 2021 Shift 2]
Match List-I with List-II :

Choose the correct answer from the options given below :
[22 Jul 2021 Shift 2]
Q.94 Correct
Q.94 In-correct
Q.94 Unattempt
For a series LCR circuit with R=100Ω,L=0.5mH and C=0.1pF connected across220V−50Hz AC supply, the phase angle between current and supplied voltage and the nature of the circuit is :
[20 Jul 2021 Shift 2]
For a series LCR circuit with R=100Ω,L=0.5mH and C=0.1pF connected across220V−50Hz AC supply, the phase angle between current and supplied voltage and the nature of the circuit is :
[20 Jul 2021 Shift 2]
Q.95 Correct
Q.95 In-correct
Q.95 Unattempt
A series LCR circuit of R=5Ω,L=20mH and C=0.5µF is connected across an AC supply of250V, having variable frequency. The power dissipated at resonance condition is _______ ×102W.
[20 Jul 2021 Shift 2]
A series LCR circuit of R=5Ω,L=20mH and C=0.5µF is connected across an AC supply of250V, having variable frequency. The power dissipated at resonance condition is _______ ×102W.
[20 Jul 2021 Shift 2]
Q.96 Correct
Q.96 In-correct
Q.96 Unattempt
AC voltage V(t)=20 sinωt of frequency 50Hz is applied to a parallel plate capacitor. The separation between the plates is 2mm and the area is 1m2.
The amplitude of the oscillating displacement current for the applied AC voltage is _______.
[ Take ε0=8.85×10−12F∕m]
[20 Jul 2021 Shift 1]
AC voltage V(t)=20 sinωt of frequency 50Hz is applied to a parallel plate capacitor. The separation between the plates is 2mm and the area is 1m2.
The amplitude of the oscillating displacement current for the applied AC voltage is _______.
[ Take ε0=8.85×10−12F∕m]
[20 Jul 2021 Shift 1]
Q.97 Correct
Q.97 In-correct
Q.97 Unattempt
In an LCR series circuit, an inductor 30mH and a resistor 1Ω are connected to an AC source of angular frequency 300rad∕s. The value of capacitance for which, the current leads the voltage by 45° is
1
x
×10−3F. Then the value of x is ______.
[20 Jul 2021 Shift 1]
In an LCR series circuit, an inductor 30mH and a resistor 1Ω are connected to an AC source of angular frequency 300rad∕s. The value of capacitance for which, the current leads the voltage by 45° is
1
x
×10−3F. Then the value of x is ______.
[20 Jul 2021 Shift 1]
Q.98 Correct
Q.98 In-correct
Q.98 Unattempt
A capacitor of capacitance C=1µF is suddenly connected to a battery of 100 volt through a resistance R=100Ω. The time taken for the capacitor to be charged to get 50V is :
[ Take ln‌2=0.69]
[27 Jul 2021 Shift 1]

A capacitor of capacitance C=1µF is suddenly connected to a battery of 100 volt through a resistance R=100Ω. The time taken for the capacitor to be charged to get 50V is :
[ Take ln‌2=0.69]
[27 Jul 2021 Shift 1]
Q.99 Correct
Q.99 In-correct
Q.99 Unattempt
An inductor of 10mH is connected to a 20Vbattery through a resistor of 10kΩ and a switch.
After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after 1µs is
x
100
mA. Then xis equal to ______. (Take e−1=0.37 )
[25 Jul 2021 Shift 1]
An inductor of 10mH is connected to a 20Vbattery through a resistor of 10kΩ and a switch.
After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after 1µs is
x
100
mA. Then xis equal to ______. (Take e−1=0.37 )
[25 Jul 2021 Shift 1]
Q.100 Correct
Q.100 In-correct
Q.100 Unattempt
An AC circuit has an inductor and a resistor of resistance R in series, such that XL=3R. Now, a capacitor is added in series such that XC=2R. The ratio of new power factor with the old power factor of the circuit is √5:x The valueof x is.
[27 Aug 2021 Shift 2]
An AC circuit has an inductor and a resistor of resistance R in series, such that XL=3R. Now, a capacitor is added in series such that XC=2R. The ratio of new power factor with the old power factor of the circuit is √5:x The valueof x is.
[27 Aug 2021 Shift 2]
Q.101 Correct
Q.101 In-correct
Q.101 Unattempt
The alternating current is given by i={√42‌sin(
2π
T
t)+10}A
The rms value of this current is ........ A.
[27 Aug 2021 Shift 1]
The alternating current is given by i={√42‌sin(
2π
T
t)+10}A
The rms value of this current is ........ A.
[27 Aug 2021 Shift 1]
Q.102 Correct
Q.102 In-correct
Q.102 Unattempt
In the given circuit the AC source has ω=100‌rad‌s−1. Considering the inductor and capacitor to be ideal, what will be the current / flowing through the circuit?

[26 Aug 2021 Shift 2]
In the given circuit the AC source has ω=100‌rad‌s−1. Considering the inductor and capacitor to be ideal, what will be the current / flowing through the circuit?

[26 Aug 2021 Shift 2]
Q.103 Correct
Q.103 In-correct
Q.103 Unattempt
A series L−C−R circuit driven by 300V at a frequency of 50‌Hz contains a resistance R=3kΩ, an inductor of inductive reactance XL=250πΩ and an unknown capacitor. The value of capacitance to maximise the average power should be (Take,π2=10)
[26 Aug 2021 Shift 1]
A series L−C−R circuit driven by 300V at a frequency of 50‌Hz contains a resistance R=3kΩ, an inductor of inductive reactance XL=250πΩ and an unknown capacitor. The value of capacitance to maximise the average power shouldbe (Take,π2=10)
[26 Aug 2021 Shift 1]
Q.104 Correct
Q.104 In-correct
Q.104 Unattempt
At very high frequencies, the effective impedance of the given circuit will be ............Ω.

[31 Aug 2021 Shift 2]
At very high frequencies, the effective impedance of the given circuit will be ............Ω.

[31 Aug 2021 Shift 2]
Q.105 Correct
Q.105 In-correct
Q.105 Unattempt
As shown in the figure, a battery of emf ∈ is connected to an inductor L and resistance R in series. The switch is closed at t=0. The total charge that flows from the battery, between t =0 and t=tc(t is the time constant of the circuit) is:
[8 Jan. 2020 II]

As shown in the figure, a battery of emf ∈ is connected to an inductor L and resistance R in series. The switch is closed at t=0. The total charge that flows from the battery, between t =0 and t=tc(t is the time constant of the circuit) is:
[8 Jan. 2020 II]
Q.106 Correct
Q.106 In-correct
Q.106 Unattempt
A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant ' b ', the correct equivalence would be:
[7 Jan. 2020 I]
A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant ' b ', the correct equivalence would be:
[7 Jan. 2020 I]
Q.107 Correct
Q.107 In-correct
Q.107 Unattempt
An emf of 20 V is applied at time t=0 to a circuit containing in series 10 mH inductor and 5 Ω resistor. The ratio of the currents at time t=∞ and at t = 40 s is close to:
(Take e2=7.389)
[7 Jan. 2020 II]
An emf of 20 V is applied at time t=0 to a circuit containing in series 10 mH inductor and 5 Ω resistor. The ratio of the currents at time t=∞ and at t = 40 s is close to:
(Take e2=7.389)
[7 Jan. 2020 II]
Q.108 Correct
Q.108 In-correct
Q.108 Unattempt
A part of a complete circuit is shown in the figure. At some instant, the value of current I is 1 A and it is decreasing at a rate of 102As–1 . The value of the potential difference VP−VQ , (in volts) at that instant, is ______.

[NA Sep. 06, 2020 (I)]
A part of a complete circuit is shown in the figure. At some instant, the value of current I is 1 A and it is decreasing at a rate of 102As–1 . The value of the potential difference VP−VQ , (in volts) at that instant, is ______.

[NA Sep. 06, 2020 (I)]
Q.109 Correct
Q.109 In-correct
Q.109 Unattempt
An AC circuit has R = 100 Ω, C = 2 µF and L = 80 mH, connected in series. The quality factor of the circuit is :
[Sep. 06, 2020 (I)]
An AC circuit has R = 100 Ω, C = 2 µF and L = 80 mH, connected in series. The quality factor of the circuit is :
[Sep. 06, 2020 (I)]
Q.110 Correct
Q.110 In-correct
Q.110 Unattempt
In a series LR circuit, power of 400 W is dissipated from a source of 250 V, 50 Hz. The power factor of the circuit is 0.8. In order to bring the power factor to unity, a capacitor of value C is added in series to the L and R. Taking the value C as (
n
3π
)µF , then value of n is ______.
[NA Sep. 06, 2020 (II)]
In a series LR circuit, power of 400 W is dissipated from a source of 250 V, 50 Hz. The power factor of the circuit is 0.8. In order to bring the power factor to unity, a capacitor of value C is added in series to the L and R. Taking the value C as (
n
3π
)µF , then value of n is ______.
[NA Sep. 06, 2020 (II)]
Q.111 Correct
Q.111 In-correct
Q.111 Unattempt
A series L−R circuit is connected to a battery of emf‌V. If the circuit is switched on at t=0, then the time at which the energy stored in the inductor reaches (
1
n
) times of its maximum value, is:
[Sep. 04, 2020 (II)]
A series L−R circuit is connected to a battery of emf‌V. If the circuit is switched on at t=0, then the time at which the energy stored in the inductor reaches (
1
n
) times of its maximum value, is:
[Sep. 04, 2020 (II)]
Q.112 Correct
Q.112 In-correct
Q.112 Unattempt
A 750 Hz, 20 V (rms) source is connected to a resistance of 100 Ω, an inductance of 0.1803 H and a capacitance of 10 µF all in series. The time in which the resistance (heat capacity 2 J/°C) will get heated by 10°C. (assume no loss of heat to the surroundings) is close to :
[Sep. 03, 2020 (I)]
A 750 Hz, 20 V (rms) source is connected to a resistance of 100 Ω, an inductance of 0.1803 H and a capacitance of 10 µF all in series. The time in which the resistance (heat capacity 2 J/°C) will get heated by 10°C. (assume no loss of heat to the surroundings) is close to :
[Sep. 03, 2020 (I)]
Q.113 Correct
Q.113 In-correct
Q.113 Unattempt
An inductance coil has a reactance of 100Ω. When an AC signal of frequency 1000Hz is applied to the coil, the applied voltage leads the current by 45°. The self-inductance of the coil is :
[Sep. 02, 2020 (II)]
An inductance coil has a reactance of 100Ω. When an AC signal of frequency 1000Hz is applied to the coil, the applied voltage leads the current by 45°. The self-inductance of the coil is :
[Sep. 02, 2020 (II)]
Q.114 Correct
Q.114 In-correct
Q.114 Unattempt
TOPIC 3 - Transformers and LCOscillations
For the given input voltage waveform Vin (t), the output voltage waveform V0(t), across the capacitor is correctly depicted by:

[Sep. 06, 2020 (I)]
TOPIC 3 - Transformers and LCOscillations
For the given input voltage waveform Vin (t), the output voltage waveform V0(t), across the capacitor is correctly depicted by:

[Sep. 06, 2020 (I)]
Q.115 Correct
Q.115 In-correct
Q.115 Unattempt
In the figure shown, a circuit contains two identical resistors with resistance R = 5 Ω and an inductance with L = 2 mH. An ideal battery of 15 V is connected in the circuit. What will be the current through the battery long after the switch is closed?

[12 Jan. 2019 I]
In the figure shown, a circuit contains two identical resistors with resistance R = 5 Ω and an inductance with L = 2 mH. An ideal battery of 15 V is connected in the circuit. What will be the current through the battery long after the switch is closed?

[12 Jan. 2019 I]
Q.116 Correct
Q.116 In-correct
Q.116 Unattempt
In the above circuit, C=
√3
2
µF,R2=20Ω,L=
√3
10
H andR1=10Ω. Current in L−R1 path is I1 and in C−R2 path it isI2. The voltage of A. C source is given by,V=200√2‌sin(100 t) volts. The phase difference between I1 and I2 is :
[12 Jan. 2019 II]

In the above circuit, C=
√3
2
µF,R2=20Ω,L=
√3
10
H andR1=10Ω. Current in L−R1 path is I1 and in C−R2 path it isI2. The voltage of A. C source is given by,V=200√2‌sin(100 t) volts. The phase difference between I1 and I2 is :
[12 Jan. 2019 II]
Q.117 Correct
Q.117 In-correct
Q.117 Unattempt
In the circuit shown,
the switch S1 is closed at time t=0 and the switch S2 is kept open. At some later time (t0), the switch S1 is opened and S2 is closed. the behaviour of the current I as a function of time 't' is given by:
[11 Jan. 2019 II]
In the circuit shown,

the switch S1 is closed at time t=0 and the switch S2 is kept open. At some later time (t0), the switch S1 is opened and S2 is closed. the behaviour of the current I as a function of time 't' is given by:
[11 Jan. 2019 II]
Q.118 Correct
Q.118 In-correct
Q.118 Unattempt
A series AC circuit containing an inductor (20mH), a capacitor (120µF) and a resistor (60Ω) is driven by an AC source of 24V∕50Hz. The energy dissipated in the circuit in 60 s is:
[9 Jan. 2019 I]
A series AC circuit containing an inductor (20mH), a capacitor (120µF) and a resistor (60Ω) is driven by an AC source of 24V∕50Hz. The energy dissipated in the circuit in 60 s is:
[9 Jan. 2019 I]
Q.119 Correct
Q.119 In-correct
Q.119 Unattempt
In LC circuit the inductance L=40 mH and capacitance C =100µF. If a voltage V(t)=10‌sin(314t) is applied to the circuit, the current in the circuit is given as:
[9 Jan. 2019 II]
In LC circuit the inductance L=40 mH and capacitance C =100µF. If a voltage V(t)=10‌sin(314t) is applied to the circuit, the current in the circuit is given as:
[9 Jan. 2019 II]
Q.120 Correct
Q.120 In-correct
Q.120 Unattempt
A power transmission line feeds input power at 2300 Vto a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be:
[9 Jan. 2019 II]
A power transmission line feeds input power at 2300 Vto a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be:
[9 Jan. 2019 II]
Q.121 Correct
Q.121 In-correct
Q.121 Unattempt
An alternating voltage v(t) = 220 sin 100Ât volt is applied to a purely resistive load of 50Ω. The time taken for the current to rise from half of the peak value to the peak value is :
[8 April 2019 I]
An alternating voltage v(t) = 220 sin 100Ât volt is applied to a purely resistive load of 50Ω. The time taken for the current to rise from half of the peak value to the peak value is :
[8 April 2019 I]
Q.122 Correct
Q.122 In-correct
Q.122 Unattempt
Consider the LR circuit shown in the figure. If the switch S is closed at t=0 then the amount of charge that passes through the battery between t=0 and t=
L
R
 is :

[12 April 2019 II]
Consider the LR circuit shown in the figure. If the switch S is closed at t=0 then the amount of charge that passes through the battery between t=0 and t=
L
R
 is :

[12 April 2019 II]
Q.123 Correct
Q.123 In-correct
Q.123 Unattempt
A coil of self inductance 10 mH and resistance 0.1 Ω is connected through a switch to a battery of internal resistance 0.9 Ω. After the switch is closed, the time taken for the current to attain 80% of the saturation value is[take ln 5 = 1.6]
[10 April 2019 II]
A coil of self inductance 10 mH and resistance 0.1 Ω is connected through a switch to a battery of internal resistance 0.9 Ω. After the switch is closed, the time taken for the current to attain 80% of the saturation value is[take ln 5 = 1.6]
[10 April 2019 II]
Q.124 Correct
Q.124 In-correct
Q.124 Unattempt
A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (Joule’s heat) across resistance is equal to the rate at which magnetic energy is stored in the inductor, is :
[8 April 2019 I]
A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (Joule’s heat) across resistance is equal to the rate at which magnetic energy is stored in the inductor, is :
[8 April 2019 I]
Q.125 Correct
Q.125 In-correct
Q.125 Unattempt
A circuit connected to an ac source of emf e=e0‌sin(100t) with t in seconds, gives a phase difference of
π
4
 between the emfe and current i. Which of the following circuits will exhibit this?
[8 April 2019 II]
A circuit connected to an ac source of emf e=e0‌sin(100t) with t in seconds, gives a phase difference of
π
4
 between the emfe and current i. Which of the following circuits will exhibit this?
[8 April 2019 II]
Q.126 Correct
Q.126 In-correct
Q.126 Unattempt
A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2kW. If the current in the secondary coil is 10 A, then the input voltage and current in the primary coil are :
[10 April 2019 I]
A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2kW. If the current in the secondary coil is 10 A, then the input voltage and current in the primary coil are :
[10 April 2019 I]
Q.127 Correct
Q.127 In-correct
Q.127 Unattempt
In an a.c. circuit, the instantaneous e.m.f. and current are given by
e=100‌sin‌30‌t
i=20‌sin(30t−
π
4
)
In one cycle of a.c., the average power consumed by the circuit and the wattless current are, respectively:
[2018]
In an a.c. circuit, the instantaneous e.m.f. and current are given by
e=100‌sin‌30‌t
i=20‌sin(30t−
π
4
)
In one cycle of a.c., the average power consumed by the circuit and the wattless current are, respectively:
[2018]
Q.128 Correct
Q.128 In-correct
Q.128 Unattempt
For an RLC circuit driven with voltage of amplitude vm and frequency ω0=
1
√LC
 the current exhibits resonance. The quality factor, Q is given by:
[2018]
For an RLC circuit driven with voltage of amplitude vm and frequency ω0=
1
√LC
 the current exhibits resonance. The quality factor, Q is given by:
[2018]
Q.129 Correct
Q.129 In-correct
Q.129 Unattempt
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns, giving the output power at 230 V. If the current in the primary of the transformer is 5 A, and its efficiency is 90%, the output current would be:
[Online April 16, 2018]
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns, giving the output power at 230 V. If the current in the primary of the transformer is 5 A, and its efficiency is 90%, the output current would be:
[Online April 16, 2018]
Q.130 Correct
Q.130 In-correct
Q.130 Unattempt
A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current I=I0‌cos(ωt). The emf induced in the smaller inner loop is nearly:
[Online April 8, 2017]
A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current I=I0‌cos(ωt). The emf induced in the smaller inner loop is nearly:
[Online April 8, 2017]
Q.131 Correct
Q.131 In-correct
Q.131 Unattempt
A sinusoidal voltage of peak value 283V and angular frequency 320∕s is applied to a series LCR circuit. Given that R=5Ω,L=25mH and C=1000µF. The total impedance, and phase difference between the voltage across the source and the current will respectively be :
[Online April 9, 2017]
A sinusoidal voltage of peak value 283V and angular frequency 320∕s is applied to a series LCR circuit. Given that R=5Ω,L=25mH and C=1000µF. The total impedance, and phase difference between the voltage across the source and the current will respectively be :
[Online April 9, 2017]
Q.132 Correct
Q.132 In-correct
Q.132 Unattempt
An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V (rms), 50 Hz AC supply, the series inductor needed for it to work is close to :
[2016]
An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V (rms), 50 Hz AC supply, the series inductor needed for it to work is close to :
[2016]
Q.133 Correct
Q.133 In-correct
Q.133 Unattempt
A series LR circuit is connected to a voltage source with V(t)=V0‌sin‌ω‌t. After very large time, current l(t) behaves as (t0>>
L
R
):
[Online April 9, 2016]
A series LR circuit is connected to a voltage source with V(t)=V0‌sin‌ω‌t. After very large time, current l(t) behaves as (t0>>
L
R
):
[Online April 9, 2016]
Q.134 Correct
Q.134 In-correct
Q.134 Unattempt
An inductor (L=0.03H) and a resistor (R=0.15kΩ) are connected in series to a battery of 15V emf in a circuit shown below. The key K1 has been kept closed for a long time. Then at t=0,K1 is opened and key K2 is closed simultaneously. At t=1ms, the current in the circuit will be: (e5≅150)

[2015]
An inductor (L=0.03H) and a resistor (R=0.15kΩ) are connected in series to a battery of 15V emf in a circuit shown below. The key K1 has been kept closed for a long time. Then at t=0,K1 is opened and key K2 is closed simultaneously. At t=1ms, the current in the circuit will be: (e5≅150)

[2015]
Q.135 Correct
Q.135 In-correct
Q.135 Unattempt
An LCR circuit is equivalent to a damped pendulum. In an LCR circuit the capacitor is charged to Q0 and then connected to the L and R as shown below :
If a student plots graphs of the square of maximum charge (QMax2) on the capacitor with time(t) for two different values L1 and L2(L1>L2) of L then which of the following represents this graph correctly? (plots are schematic and not drawn to scale)
[2015]
An LCR circuit is equivalent to a damped pendulum. In an LCR circuit the capacitor is charged to Q0 and then connected to the L and R as shown below :

If a student plots graphs of the square of maximum charge (QMax2) on the capacitor with time(t) for two different values L1 and L2(L1>L2) of L then which of the following represents this graph correctly? (plots are schematic and not drawn to scale)
[2015]
Q.136 Correct
Q.136 In-correct
Q.136 Unattempt
For the LCR circuit, shown here, the current is observed to lead the applied voltage. An additional capacitor C’, when joined with the capacitor C present in the circuit, makes the power factor of the circuit unity. The capacitor C’, must have been connected in :

[Online April 11, 2015]
For the LCR circuit, shown here, the current is observed to lead the applied voltage. An additional capacitor C’, when joined with the capacitor C present in the circuit, makes the power factor of the circuit unity. The capacitor C’, must have been connected in :

[Online April 11, 2015]
Q.137 Correct
Q.137 In-correct
Q.137 Unattempt
In the circuits (a) and (b) switches S1 and S2 are closed at t=0 and are kept closed for a long time. The variation of current in the two circuits for t‌geq‌0 are roughly shown by figure (figures are schematic and not drawn to scale):

[Online April 10, 2015]
In the circuits (a) and (b) switches S1 and S2 are closed at t=0 and are kept closed for a long time. The variation of current in the two circuits for t‌geq‌0 are roughly shown by figure (figures are schematic and not drawn to scale):

[Online April 10, 2015]
Q.138 Correct
Q.138 In-correct
Q.138 Unattempt
A sinusoidal voltage V(t) = 100 sin (500t) is applied across a pure inductance of L = 0.02 H. The current through the coil is:
[Online April 12, 2014]
A sinusoidal voltage V(t) = 100 sin (500t) is applied across a pure inductance of L = 0.02 H. The current through the coil is:
[Online April 12, 2014]
Q.139 Correct
Q.139 In-correct
Q.139 Unattempt
In the circuit shown here, the point ‘C’ is kept connected to point ‘A’ till the current flowing through the circuit becomes constant. Afterward, suddenly, point ‘C’ is disconnected from point ‘A’ and connected to point ‘B’ at time t = 0. Ratio of the voltage across resistance and the inductor at t = L/R will be equal to:

[2014]
In the circuit shown here, the point ‘C’ is kept connected to point ‘A’ till the current flowing through the circuit becomes constant. Afterward, suddenly, point ‘C’ is disconnected from point ‘A’ and connected to point ‘B’ at time t = 0. Ratio of the voltage across resistance and the inductor at t = L/R will be equal to:

[2014]
Q.140 Correct
Q.140 In-correct
Q.140 Unattempt
When the rms voltages VL,VC and VR are measured respectively across the inductor L, the capacitor C and the resistor R in a series LCR circuit connected to an AC source,it is found that the ratio VL:VC:VR=1:2:3. If the rms voltage of the AC sources is 100V, the VR is close to:
[Online April 9, 2014]
When the rms voltages VL,VC and VR are measured respectively across the inductor L, the capacitor C and the resistor R in a series LCR circuit connected to an AC source,it is found that the ratio VL:VC:VR=1:2:3. If the rms voltage of the AC sources is 100V, the VR is close to:
[Online April 9, 2014]
Q.141 Correct
Q.141 In-correct
Q.141 Unattempt
In an LCR circuit as shown below both switches are open initially. Now switch S1 is closed, S2 kept open. ( q is charge on the capacitor and τ=RC is Capacitive time constant). Which of the following statement is correct?

[2013]
In an LCR circuit as shown below both switches are open initially. Now switch S1 is closed, S2 kept open. ( q is charge on the capacitor and τ=RC is Capacitive time constant). Which of the following statement is correct?

[2013]
Q.142 Correct
Q.142 In-correct
Q.142 Unattempt
A series LR circuit is connected to an ac source of frequency ω and the inductive reactance is equal to 2R. A capacitance of capacitive reactance equal to R is added in series with L and R. The ratio of the new power factor to the old one is:
[Online April 25, 2013]
A series LR circuit is connected to an ac source of frequency ω and the inductive reactance is equal to 2R. A capacitance of capacitive reactance equal to R is added in series with L and R. The ratio of the new power factor to the old one is:
[Online April 25, 2013]
Q.143 Correct
Q.143 In-correct
Q.143 Unattempt
When resonance is produced in a series LCR circuit, then which of the following is not correct ?
[Online April 25, 2013]
When resonance is produced in a series LCR circuit, then which of the following is not correct ?
[Online April 25, 2013]
Q.144 Correct
Q.144 In-correct
Q.144 Unattempt
The plot given below is of the average power delivered to an LRC circuit versus frequency. The quality factor of the circuit is :

[Online April 23, 2013]
The plot given below is of the average power delivered to an LRC circuit versus frequency. The quality factor of the circuit is :

[Online April 23, 2013]
Q.145 Correct
Q.145 In-correct
Q.145 Unattempt
In a series L−C -R circuit, C=10−11 Farad, L=10−5 Henry and R=100Ohm, when a constant D.C. voltage E is applied to the circuit, the capacitor acquires a charge 10−9C. The D. C. source is replaced by a sinusoidal voltage source in which the peak voltage E0 is equal to the constant D.C. voltage E. At resonance the peak value of the charge acquired by the capacitor will be :
[Online April 22, 2013]
In a series L−C -R circuit, C=10−11 Farad, L=10−5 Henry and R=100Ohm, when a constant D.C. voltage E is applied to the circuit, the capacitor acquires a charge 10−9C. The D. C. source is replaced by a sinusoidal voltage source in which the peak voltage E0 is equal to the constant D.C. voltage E. At resonance the peak value of the charge acquired by the capacitor will be :
[Online April 22, 2013]
Q.146 Correct
Q.146 In-correct
Q.146 Unattempt
An LCR circuit as shown in the figure is connected to a voltage source Vac whose frequency can be varied.
The frequency, at which the voltage across the resistor is maximum, is :
[Online April 22, 2013]
An LCR circuit as shown in the figure is connected to a voltage source Vac whose frequency can be varied.

The frequency, at which the voltage across the resistor is maximum, is :
[Online April 22, 2013]
Q.147 Correct
Q.147 In-correct
Q.147 Unattempt
In the circuit shown here, the voltage across E and C are respectively 300 V and 400 V. The voltage E of the ac source is :

[Online April 9, 2013]
In the circuit shown here, the voltage across E and C are respectively 300 V and 400 V. The voltage E of the ac source is :

[Online April 9, 2013]
Q.148 Correct
Q.148 In-correct
Q.148 Unattempt
A resistance R and a capacitance C are connected in series to a battery of negligible internal resistance through a key. The key is closed at t = 0. If after t sec the voltage across the capacitance was seven times the voltage across R, the value of t is
[Online May 12, 2012]
A resistance R and a capacitance C are connected in series to a battery of negligible internal resistance through a key. The key is closed at t = 0. If after t sec the voltage across the capacitance was seven times the voltage across R, the value of t is
[Online May 12, 2012]
Q.149 Correct
Q.149 In-correct
Q.149 Unattempt
In an LCR circuit shown in the following figure, what will be the readings of the voltmeter across the resistor and ammeter if an a.c. source of 220V and 100 Hz is connected to it as shown?

[Online May 7, 2012]
In an LCR circuit shown in the following figure, what will be the readings of the voltmeter across the resistor and ammeter if an a.c. source of 220V and 100 Hz is connected to it as shown?

[Online May 7, 2012]
Q.150 Correct
Q.150 In-correct
Q.150 Unattempt
A fully charged capacitor C with initial charge q0 is connected to a coil of self inductance L at t=0. The time at which the energy is stored equally between the electric and the magnetic fields is:
[2011]
A fully charged capacitor C with initial charge q0 is connected to a coil of self inductance L at t=0. The time at which the energy is stored equally between the electric and the magnetic fields is:
[2011]
Q.151 Correct
Q.151 In-correct
Q.151 Unattempt
A resistor ' R ' and 2µF capacitor in series is connected through a switch to 200V direct supply. Across the capacitor is a neon bulb that lights up at 120V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. (log102.5=0.4)
[2011]
A resistor ' R ' and 2µF capacitor in series is connected through a switch to 200V direct supply. Across the capacitor is a neon bulb that lights up at 120V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. (log102.5=0.4)
[2011]
Q.152 Correct
Q.152 In-correct
Q.152 Unattempt
Combination of two identical capacitors, a resistor R and a dc voltage source of voltage 6V is used in an experiment on a (C-R) circuit. It is found that for a parallel combination of the capacitor the time in which the voltage of the fully charged combination reduces to half its original voltage is 10 second. For series combination the time for needed for reducing the voltage of the fully charged series combination by half is
[2011 RS]
Combination of two identical capacitors, a resistor R and a dc voltage source of voltage 6V is used in an experiment on a (C-R) circuit. It is found that for a parallel combination of the capacitor the time in which the voltage of the fully charged combination reduces to half its original voltage is 10 second. For series combination the time for needed for reducing the voltage of the fully charged series combination by half is
[2011 RS]
Q.153 Correct
Q.153 In-correct
Q.153 Unattempt
In the circuit shown below, the key K is closed at t = 0. The current through the battery is

[2010]
In the circuit shown below, the key K is closed at t = 0. The current through the battery is

[2010]
Q.154 Correct
Q.154 In-correct
Q.154 Unattempt
In a series LCR circuit R = 200Ω and the voltage and the frequency of the main supply is 220V and 50 Hz respectively. On taking out the capacitance from the circuit the current lags behind the voltage by 30°. On taking out the inductor from the circuit the current leads the voltage by 30°. The power dissipated in the LCR circuit is
[2010]
In a series LCR circuit R = 200Ω and the voltage and the frequency of the main supply is 220V and 50 Hz respectively. On taking out the capacitance from the circuit the current lags behind the voltage by 30°. On taking out the inductor from the circuit the current leads the voltage by 30°. The power dissipated in the LCR circuit is
[2010]
Q.155 Correct
Q.155 In-correct
Q.155 Unattempt

An inductor of inductance L=400mH and resistors of resistance R1=2Ω and R2=2Ω are connected to a battery of emf 12V as shown in the figure. The internal resistance of the battery is negligible. The switch S is closed at t=0. The potential drop across L as a function of time is
[2009]

An inductor of inductance L=400mH and resistors of resistance R1=2Ω and R2=2Ω are connected to a battery of emf 12V as shown in the figure. The internal resistance of the battery is negligible. The switch S is closed at t=0. The potential drop across L as a function of time is
[2009]
Q.156 Correct
Q.156 In-correct
Q.156 Unattempt
In an a.c. circuit the voltage applied is E=E0‌sin‌ω‌t. The resulting current in the circuit is I=I0‌sin(ωt−
π
2
). The power consumption in the circuit is given by
[2007]
In an a.c. circuit the voltage applied is E=E0‌sin‌ω‌t. The resulting current in the circuit is I=I0‌sin(ωt−
π
2
). The power consumption in the circuit is given by
[2007]
Q.157 Correct
Q.157 In-correct
Q.157 Unattempt
In a series resonant LCR circuit, the voltage across R is 100 volts and R=1kΩ with C=2µF. The resonant frequency omega is 200‌rad∕s. At resonance the voltage across L is
[2006]
In a series resonant LCR circuit, the voltage across R is 100 volts and R=1kΩ with C=2µF. The resonant frequency omega is 200‌rad∕s. At resonance the voltage across L is
[2006]
Q.158 Correct
Q.158 In-correct
Q.158 Unattempt
An inductor (L = 100 mH), a resistor (R = 100 Ω) and a battery (E = 100 V) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The current in the circuit 1 ms after the short circuit is

[2006]
An inductor (L = 100 mH), a resistor (R = 100 Ω) and a battery (E = 100 V) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The current in the circuit 1 ms after the short circuit is

[2006]
Q.159 Correct
Q.159 In-correct
Q.159 Unattempt
In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil is
[2006]
In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil is
[2006]
Q.160 Correct
Q.160 In-correct
Q.160 Unattempt
The phase difference between the alternating current and emf is
π
2
 . Which of the following cannot be the constituent of the circuit?
[2005]
The phase difference between the alternating current and emf is
π
2
 . Which of the following cannot be the constituent of the circuit?
[2005]
Q.161 Correct
Q.161 In-correct
Q.161 Unattempt
A circuit has a resistance of 12 ohm and an impedance of 15 ohm. The power factor of the circuit will be
[2005]
A circuit has a resistance of 12 ohm and an impedance of 15 ohm. The power factor of the circuit will be
[2005]
Q.162 Correct
Q.162 In-correct
Q.162 Unattempt
A coil of inductance 300 mH and resistance 2 Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
[2005]
A coil of inductance 300 mH and resistance 2 Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
[2005]
Q.163 Correct
Q.163 In-correct
Q.163 Unattempt
The self inductance of the motor of an electric fan is 10 H.
In order to impart maximum power at 50 Hz, it should be connected to a capacitance of
[2005]
The self inductance of the motor of an electric fan is 10 H.
In order to impart maximum power at 50 Hz, it should be connected to a capacitance of
[2005]
Q.164 Correct
Q.164 In-correct
Q.164 Unattempt
In a uniform magnetic field of induction B a wire in the form of a semicircle of radius r rotates about the diameter of the circle with an angular frequency ω. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is R, the mean power generated per period of rotation is
[2004]
In a uniform magnetic field of induction B a wire in the form of a semicircle of radius r rotates about the diameter of the circle with an angular frequency ω. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is R, the mean power generated per period of rotation is
[2004]
Q.165 Correct
Q.165 In-correct
Q.165 Unattempt
Alternating current can not be measured by D.C. ammeter because
[2004]
Alternating current can not be measured by D.C. ammeter because
[2004]
Q.166 Correct
Q.166 In-correct
Q.166 Unattempt
In an LCR series a.c. circuit, the voltage across each of the components, L, C and R is 50V. The voltage across the LC combination will be
[2004]
In an LCR series a.c. circuit, the voltage across each of the components, L, C and R is 50V. The voltage across the LC combination will be
[2004]
Q.167 Correct
Q.167 In-correct
Q.167 Unattempt
In a LCR circuit capacitance is changed from C to 2 C. For the resonant frequency to remain unchanged, the inductance should be changed from L to
[2004]
In a LCR circuit capacitance is changed from C to 2 C. For the resonant frequency to remain unchanged, the inductance should be changed from L to
[2004]
Q.168 Correct
Q.168 In-correct
Q.168 Unattempt
In an oscillating LC circuit the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic field is
[2003]
In an oscillating LC circuit the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic field is
[2003]
Q.169 Correct
Q.169 In-correct
Q.169 Unattempt
The core of any transformer is laminated so as to
[2003]
The core of any transformer is laminated so as to
[2003]
Q.170 Correct
Q.170 In-correct
Q.170 Unattempt
The power factor of an AC circuit having resistance (R) and inductance (L) connected in series and an angular velocity ω is
[2002]
The power factor of an AC circuit having resistance (R) and inductance (L) connected in series and an angular velocity ω is
[2002]
Q.171 Correct
Q.171 In-correct
Q.171 Unattempt
The inductance between A and D is

[2002]
The inductance between A and D is

[2002]
Q.172 Correct
Q.172 In-correct
Q.172 Unattempt
In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary coil is 4 A, then that in the secondary coil is
[2002]
In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary coil is 4 A, then that in the secondary coil is
[2002]
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