Wien's Displacement Law - Practice Questions & MCQ

Wien's displacement law states that the wavelength (i.e $\lambda_{\text {max }}$ ) for which the emissive power of a black body is maximum is inversely proportional to the absolute temperature ( T ) of the black body.

Or Mathematically we can write that

$$
\lambda_{\max } * T=b=\mathrm{constant}
$$

Where $\mathbf{b}$ is a constant of proportionality which is known as Wien's displacement constant.
Value of b is given as $b=2.89 * 10^{-3} \mathrm{mK}$

With the help of this law, we can say that 

As the temperature of the body increases, the wavelength at which the spectral intensity () is maximum shifts towards left, as shown in the below figure.

I.e

If $T_1<T_2<T_3$
Then $\lambda_{m_1}>\lambda_{m_2}>\lambda_{m_3}$

• Wien's displacement law is useful for determining the temperatures of hot radiant objects such as stars, and it is also useful for a determination of the temperature of any radiant object whose temperature is far above that of its surroundings.