The balck body specturm of an object `O_(1)` is such that its radiant intensity (i.e., intensity per unit wavelength interval) is maximum at a wavelength of `200 nm`. Another object `Q_(2)` has the maximum radiant intensity at `600nm`. The ratio of power emitted per unit area by source `Q_(1)` to that of souce `O_(2)` is

Options

A. `1:81`
B. `1:9`
C. `9:1`
D. `81:1`

Answer

D

Explanation

From Wien's Displacement law,
`lambda_(m)T= b= a constant or lambda_(m)=b/T`
From Stefan's law, `E prop T^(4)`
`:. (E_(1))/(E_(2))=(T_(1)^(4))/(T_(2)^(4))= (lambda_(m_(2))^(4))/(lambda_(m_(1)^(4)))= ((600)^(4))/((200)^(4))= (81)/1`