two black metallic spheres of radius 4m at 2000K and 1m at 4000K will have ratio of energy radiation

swati agarwal

two black metallic spheres of radius 4m at 2000K and 1m at 4000K will have ratio of energy radiation as

charanjit ghai

since E=Pt where t is the time for emmisivity of radiant energy.so

E = sigma A absillion T^4 t

where sigma is stefan;s constant

A is the area for radiation

absillion is emissivity

this implies E1/E2 = sigma 4 pie 4^2 (2000)^4 t /sigma 4 pie 1^2 (4000)^4 t

E1/E2= 16x 1/16 = 1

Krishna Gopal Singh

Right answer Charanjeet. Well done.