NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
Two electric lamps A and B radiate the same power. Their filaments have the same dimensions and have emissivities e A and e B respectively. Their surface temperatures are T A and T B . The ratio T A T B will be equal to
Options
- A( e B e A ) 1 / 4
- B( e B e A ) 1 / 2
- C( e A e B ) 1 / 2
- D( e A e B ) 1 / 4
Correct answer
A. ( e B e A ) 1 / 4
Step-by-step solution
The power radiated by a filament is P = e A σ T 4 (where e = emissivity, σ = Stefan's constant and T = surface temperature) Here, e T 4 = constant or e A T A 4 = e B T B 4