$\lambda_{\mathrm{m}} \cdot \mathrm{T}=\mathrm{b}$
i.e. $\mathrm{T} \propto \frac{1}{\lambda_{\mathrm{m}}}$
Here, $\lambda_{\mathrm{m}}$ becomes half.
$\therefore$ Temperature doubles.
Also $e$ $=\sigma \mathrm{T}^{4}$
$\Rightarrow \frac{\mathrm{e}_{1}}{\mathrm{e}_{2}}=\left(\frac{\mathrm{T}_{1}}{\mathrm{T}_{2}}\right)^{4}$
$\Rightarrow \mathrm{e}_{2}=\left(\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}}\right)^{4} \cdot \mathrm{e}_{1}=(2)^{4} \cdot 16$
$=16.16=256 \mathrm{J} \mathrm{m}^{-2} \mathrm{s}^{-1}$
($\sigma$ stands for Stefan's constant)