Two spherical stars $A$ and $B$ emit blackbody radiation. The radius of $A$ is $400$ times that of $B$ and $A$ emits $10^4$ times the power emitted from $B$. The ratio $\left(\lambda_A / \lambda_B\right)$ of their wavelengths $\lambda_A$ and $\lambda_B$ at which the peaks occur in their respective radiation curves is
IIT 2015, Medium
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$\left(\frac{d Q}{d t}\right)_A=10^4\left(\frac{d Q}{d t}\right)_B$
$(400 R)^2 T_A^4=10^4\left(R^2 T_B^4\right)$
So, $2 T _{ A }= T _{ B }$ and $\frac{\lambda_{ A }}{\lambda_{ B }}=\frac{ T _{ B }}{ T _{ A }}=2$
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