JEE Main20257 Apr 2025Morning ShiftPhysicsThermal Properties of MatterActual
A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727^ C and power radiated by the wire is 94.2 W. Its emissivity is x 8 where x=_______ (Given =6.0 10⁻⁸ ~W ~m ⁻² ~K ⁻⁴, =3.14 and assume that the emissivity of wire material is same at all wavelength.)
Correct answer
0
Step-by-step solution
L =10 ~cm , ~d =0.5 ~mm , ~T =1727^ C =2000 ~K Power, P =94.2 ~W P = AT ^4 94.2= (6 10⁻⁸ )( dL )(2000)^4 94.2= (6 10⁻⁸ )(3.14)(0.5) (10⁻³ ) (10 10⁻² )(2000)^4 = 94.2 (94.2)(16) = 5 8