A body of area `0.8xx10^(-2) m^(2)` and mass `5xx10^(-4) kg` directly faces the sun on a clear day. The body has an emissivity of 0.8 and specific heat of `0.8 ca//kg` K. The surroundings are at `27^@C`. (solar constant`=1.4 kW//m^(2)`).
The maximum attainable temperature of the body is

Options

A. `396K`
B. `396^@C`
C. `85^@C`
D. `85K`

Answer

A

Explanation

The temperature becomes maximum when net rate of absorption of energy becomes equal to zero i.e., at any instant `P=(S-sigmaT^4)eA=0`
`T_(max)=((S)/(sigma))^((1)/(4))=((1.4xx10^3)/(5.67xx10^-8))^((1)/(4))=396K`