Question

For a glass plate, transmissivity and reflectivity are specified as 0.86 and 0.08 respectively, the absorptivity of the plate is

1. 0.86
2. 0.08
3. 1.00
4. 0.06

Answer 1

Correct Answer - Option 4 : 0.06

Concept:

Absorptivity (α):

Fraction of radiant energy incident upon a surface which is absorbed by it.

Reflectivity (ρ):

 Fraction of radiant energy incident upon a surface which is reflected by it.

Transmissivity (τ):

Fraction of radiant energy incident upon a surface which is transmitted through it.

For any Surface,

α + ρ + τ = 1

Calculation:

Given:

τ = 0.86, ρ = 0.08

substituting all the values in the equation we have;

α + 0.08 + 0.86 = 1

α = 1 – 0.08 – 0.86

α = 0.06