Answer
(b) $\lambda_{max,A}= 2\lambda_{max,B}$
Work Step by Step
According to Wiens displacement law $\lambda_{max} T = 2.90 \times 10^{-3}$ m.K
for blackbody A
$\lambda_{max,A} \times 3000K = 2.90 \times 10^{-3}$ m.K .......equation (1)
similarly for blackbody B
$\lambda_{max,B} \times6000K = 2.90 \times 10^{-3}$ m.K .......equation (2)
divide equation (1) by Equation (2)
$\frac{$\lambda_{max,A} \times 3000K$}{$\lambda_{max,B} \times6000K$} $= $\frac{2.90 \times 10^{-3}$ m.K}{2.90 \times 10^{-3}$ m.K} $
will give us
$\lambda_{max,A}= 2\lambda_{max,B}$
