Question

On investigation of light coming from three different stars $A,B$ and $C$ it was found that in the spectrum of $A$, the intensity of red color is maximum, in $B$ the intensity of blue color is maximum and in $C$, the intensity of yellow color is maximum. From these observations it can be concluded that,

• A. the temperature of $A$ is maximum,$B$ is minimum and $C$ is intermediate.
• B. the temperature of $A$ is maximum,$C$ is minimum and $B$ is intermediate.
• C. the temperature of $B$ is maximum,$A$ is minimum and $C$ is intermediate.
• D. the temperature of $B$ is maximum,$C$ is minimum and $A$ is intermediate.

Answer 1

The correct option is C the temperature of $B$ is maximum,$A$ is minimum and $C$ is intermediate.

We know from Weins displacement law, ${\lambda }_{m}T=b\left(\text{Wein's constant}\right)$
So, $T\propto \frac{1}{{\lambda }_m}$

It is given that,
for star$A\to {\lambda }_m={\lambda }_{red}$
for star $B\to {\lambda }_m={\lambda }_{blue}$
for star $C\to {\lambda }_m={\lambda }_{Yellow}$

Since, ${\lambda }_{red}>{\lambda }_{yellow}>{\lambda }_{blue}$

$\therefore T_A<T_C<T_B$

Hence, $\left(C\right)$ is the correct answer.