Assertion : In conduction mode of transmission of heat, transfer of heat is due to the interatomic collisions without the actual movement of atoms.

Reason: Steady state during conduction of heat through a rod means temperature gradient of all parts of the rod is same.

Assertion : In a room containing air, heat can go from one place to another by radiation only.

Reason : In conduction and convection, heat is transferred from one place to other by actual motion of heated material.

Assertion : Radiation is the fastest mode of heat transfer.

Reason : The nature of emitted radiations from ideal black body depends only on its temperature.

Assertion : Heat radiation are always obtained in infrared region of electromagnetic wave spectrum.

Reason : Complementary colour are those two colour present in the spectrum which when mixed produce white light.

Assertion : Heat radiations and light have identical properties.

Reason : A cool body does not radiate heat to the hotter surroundings.

Assertion : Coldness is felt in summer when we enter in air-conditioned room.

Reason : At every possible temperature, there is a continuous heat energy exchange between a body and its surrounding.

Assertion: IBB (Ideal Black Body) is a good emitter at high temperature.

Reason: Good emitters are good absorbers and vice versa.

Assertion: Absorptive power is a dimensionless quantity and a body having low emissive power should have low absorptive power.

Reason: The ratio of emissive power to absorptive power is same for all bodies at a given temperature and is equal to the emissive power of a black body at that temperature.

Assertion: A body that is a good radiator is also a good absorber of radiation at a given wavelength.

Reason: According to Kirchhoff's law the absorptivity of a body is equal to its emissivity at a given wavelength.