A thin wire of length l and surface area A is heated to a temperature T. Its electrci resistance is R, emissivity of its surface is e. How much electric current should be maintained through the wire so as. To maintain its temperature at T ? Assume the temperature of surroundings to be negligible compared to T. Use Stefan.s constant as `sigma` :

Options

A. `(eA sigmaT^(4))/( R )`
B. `(e sigmaT^(4)//R)^((1)/(2))`
C. `((eA sigmaT^(4))^((1)/(2)))/( R )`
D. `((eA sigmaT^(4))/( R ))^((1)/(2))`

Answer

D