Thermal Properties of Matter - Result Question 16

16. On observing light from three different stars P, Q and R, it was found that intensity of violet colour is maximum in the spectrum of $P$, the intensity of green colour is maximum in the spectrum of $R$ and the intensity of red colour is maximum in the spectrum of $Q$. If $T_P, T_Q$ and $T_R$ are the respective absolute temperature of $P, Q$ and $R$, then it can be concluded from the above observations that

[2015]

(a) $T_P>T_R>T_Q$

(b) T $ _{P}<T_R<T_Q$

(c) $T_P<T_Q<T_R$

(d) $T_P>T_Q>T_R$

Show Answer

Answer:

Correct Answer: 16. (a)

Solution:

  1. (a) From Wein’s displacement law

$\lambda_m \times T=$ constant

$P-$ max. intensity is at violet

$\Rightarrow \lambda_m$ is minimum $\Rightarrow$ temp maximum

$R-max$. intensity is at green

$\Rightarrow \lambda_m$ is moderate $\Rightarrow$ temp moderate

$Q-$ max. intensity is at red $\Rightarrow \lambda_m$ is maximum $\Rightarrow$

temp. minimum i.e., $T_p>T_R>T_Q$