A 100W bulb has tungsten filament of total length `1.0m` and radius `4xx10^(-5)m` . The emissivity of the filament is `0.8` and `sigma=6.0xx10^(-8)Wm^(-2)K^(-4)` . Calculate the temperature of the filament when the bulb is operating at correct wattage.

Answer

A

Explanation

`(Q/t)=eA(sigma)T^4`
`implies T_4=(Q)/(teA (sigma))`
`(100)/(0.8xx2xx3.144xx10^(-5)xx1xx6xx10^(-8))`
`impliesT=1697.0=1700K.`