Heat energy is incident on the surface at the rate of 1000J/min. If coefficient of absorption is and coeffiicient of reflection is 0.5 the heat energy transmitted by the surface in 5 min is

Options

A. 100J
B. 500J
C. 700 J
D. 900J

Answer

B

Explanation

Given, rate of heat energy `(Q_(1))=1000J//min`
We know that,
`1=a+r+t`
Here, coefficient of absorption (a) = 0.8
Coefficient of reflection (r) =0.1
Now,
`1=0.1+0.1+t`
`t=1-0.9`
The rate of transmitter heat energy in 5 min `Q_(t)=theta_(i)xxtxx(time)=1000xx0.1xx5=500J`