A point source of light 'S' at a distance d from the screen A produces light intensity `I_(0)` at the centre of the screen. If a completely reflecting mirror M is placed at a distance d behind the source as shown in the figure, find the intensity at the centre of the screen

Options

A. `9/10 I_(0)`
B. `10/9 I_(0)`
C. `8/9 I_(0)`
D. `9/8 I_(0)`

Answer

B

Explanation

`I_(1)=I_(0)=P/(4pid^(2))`
`I_(2)=P/(4pi(3d)^(2))`
`I=I_(1)+I_(2)=P/(4pid^(2))[1+1/9]=10/9 I_(0)`