Test: Reflectivity - Mechanical Engineering MCQ

It is total energy reflected by the body. Its value depends upon the nature of the surface of the body, its temperature and wavelength of incident radiations.

Reflectivity = fraction of total energy reflected by the body = 60/350 = 0.171.

Heat loss by convection from both sides of the plates = 2 h A d t = 1.1 W. Energy lost by reflection = 2.0 – 1.1 = 0.9 W.

It should be wavelength of incident radiation. It is the fraction of total energy reflected by the body.

It is absorbing a certain fixed amount of radiations.

Gases are known to reflect very little of the radiation incident on their surface.

For transparent body, transmissivity is zero.

Rate of reflection = pQ₀ = 218.20 W/m².

A = B + C + D.

For opaque body, sum of absorptivity and reflectivity is unity.