Question

The emissive power of a body depends on

• A. temperature
• B. wavelength
• C. mass of the body
• D. both A and B

Answer 1

Answer: (D)

both A and B

Emissive power $=\sigma ϵT^4$

And by wein's displacement law, the wavelength, ${\lambda }_{max}$ for max, Emissive power from black body is a function of temperature.

${\lambda }_{max}=\frac{2900}{T}$

( ${\lambda }_{max}$ in 'mm' and $T$ in 'K' )

So, we can say that emissive power depends on temperature and wavelength.