Thermal Properties Of Matter Ques 9
9. 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) $T_P>T_Q>T_R$
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Answer:
Correct Answer: 9.(a)
Solution:
- (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., $T_p>T_R>T_Q$
BETA
