For a perfect black body, the absorption coefficient is
For a perfect black body, the absorption coefficient is
\(a=1\)
\(a < 1\)
\(a>1\)
\(a=0\)
Solution
A perfectly black body absorbs \(100 \%\) of radiation incident on it, hence absorption coefficient \(\left(a_r\right)\) is given as
\(\begin{aligned}
a_r & =\frac{\text { amount of absorb radiation }\left(Q_a\right)}{\text { amount of incident radiation }\left(Q_i\right)} \\
& =\frac{Q_a}{Q_i}=\frac{Q_a}{Q_a} \quad\left[\because Q_a=Q_i\right] \\
& =1
\end{aligned}\)