The emission spectrum of a black body at two different temperatures are shown by curyes P and Q (as shown in figure). The ratio of the areas
under the two curves P and Q will be

Absolute temperatures of the black body corresponding to curve P and Q are in the inverse ratio of ${\mathrm{\lambda }}_{\mathrm{m}}$(Wein's displacement law).
$\mathrm{i}.\mathrm{e}., \frac{{\mathrm{T}}_{\mathrm{P}}}{{\mathrm{T}}_{\mathrm{Q}}} = \frac{1987}{2980}$

Area under curves represent the total power radiated by a body and is proportional to the fourth power of absolute temperature (Stefan's law)

$\therefore \frac{{\mathrm{A}}_{\mathrm{p}}}{{\mathrm{A}}_{\mathrm{Q}}} = {\left(\frac{{\mathrm{T}}_{\mathrm{P}}}{{\mathrm{T}}_{\mathrm{Q}}}\right)}^4= \frac{16}{81}$