(a) A body with a large reflectivity absorbs less amount of light radiations and a poor absorber is a poor emitter of radiations. Hence, a body with a large reflectivity is a poor emitter.

(b) Brass is a good conductor of heat while the wood is a bad conductor of heat. When one touches a brass tumbler, heat is conducted from the body to the brass tumbler easier than it is conducted to the wooden tray. Hence, the temperature of the body reduces to a lower value than the value when one touches the wooden tray. Thus, a brass tumbler feels colder than a wooden tray on a chilly day.

(c)

Black body radiation equation is given by:

$E=\sigma (T^4-T_0^4)$

Where,

E = Energy radiation

T = Temperature of the optical pyrometer

T${}_0$ = Temperature of open space

σ = Constant

Hence, an increase in the temperature of open space reduces the radiation energy.

When the same piece of iron is placed in a furnace, the radiation energy, E = σ T${}^4$

In this case, the radiation energy is equal to the actual heat radiated by the red hot iron and the instrument gives the correct value of its temperature.

(d) In the absence of atmospheric gases, no extra heat will be trapped. All the heat would be radiated back from the earth’s surface.

(e) The steam contains more heat in the form of latent heat (540 cal/g) than the water. So, a heating system based on the circulation of steam is more efficient in warming a building than that based on the circulation of hot water.