If 150 J of energy is incident on area ` 2m^(2)` . If `Q_(r)=15J`, coefficient of absorption is 0.6 , then amount of energy transmitted is

Options

A. 50 J
B. 45 J
C. 40 J
D. 30 J

Answer

B

Explanation

When thermal radiations (Q) fall on a body , they are partly reflected , party absorbed and partly transmitted .
`Q=Q_(a)+Q_(r)+Q_(t)` ltbr
`"and "(Q_(a))/(Q)+(Q_(r))/(Q)+(Q_(t))/(Q)=a+r+t=1`
`"or "0.6+(15)/(150)+x=1rArr0.1+0.6=x=1`
`"or "x=0.3`
Transmitting power , `t=(Qt)/(Q)`
`"or "0.3=(Q_(t))/(150)rArrQ_(t)=45 J`