• Due to high specific heat of water, it is used in hot water bags.
• As the specific heat of water is large, this means that it can absorb a large amount of heat without the temperature being raised too high.

• A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
• A body absorbs heat most if it is black and rough since rough surface has more surface area to absorb.

The Celsius scale is equivalent to the Fahrenheit scales at a temperature of -40^oC, which is proven below:

Let T_C be -40^oC

Putting the values in the above formula, we get

On solving for T_F, we get

-72=T_f -32

T_f=32-72=-40^oF

Thus, option A is the correct answer.

• Sound waves cannot be transmitted through vacuum.

• It is transmitted by the movement of particles along with the direction of the motion of the sound wave.

• Sound is a mechanical disturbance which is dependent upon a medium to travel.

• It can be transmitted through solids, liquids, and gases.

• The unit of activity of a radioactive source is Becquerel.

• One Becquerel is defined as the activity of a quantity of radioactive substance in which one nucleus decays per second.

• The Unit is named after the great scientist Henry Becquerel.

• He shared Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity.

• It is prefixed as Bq, The Becquerel succeeded the curie (Ci),an older, non-SI unit of radioactivity.

• The SI unit of Inductance is Henry.

• It is defined as the measure of electric current changes at one ampere per second resulting in an electromotive force of one volt across the inductor.

• Inductance is the property of an electric conductor or circuit that causes an electromotive force to be generated by a change in the current flowing.

• Faraday's law of induction says that any change in magnetic field through a circuit induces an electromotive force (EMF) in the conductors.

• Decible is a unit of measurement for intensity of sound.

• The human ear as a dyamic range from 0dB (threshold) to 120-130 dB.

• Normal conservation occurs at 60 db, a car horn at 110db, etc.

• Water droplets cause rainbow due to reflection & refraction of sunlight.

• It takes the form of a multicoloured circular arc.

• Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.