Question

A spherical black body with radius 12 cm radiates 640 w power at 500 K. If the radius is halved and the temperature doubled, the power radiated in watts would be
A. 5120 W
B. 640 W
C. 2560 w
D. 1280 W

Answer 1

Correct Answer - C
Ratio of powers , `P_(1)/P_(2) = A_(1)T_(1)^(4)/A_(2)T_(2)^(4)`
`P_(2)=A_(2)/A_(1)(T_(2)/T_(1))^(4) P_(1)=(1/2)^(2)(2)^(4)(640)=2560W`