At two point P and Q on screen in Young's double slit experiment, waves from slits `S_(1)` and `S_(2)` have a path difference of 0 and `(lamda)/(4)` respectively. The ratio of intensities at P and Q will be:

Options

A. `2:1`
B. `sqrt(2) :1`
C. `4:1`
D. `3:2`

Answer

A

Explanation

`Delta x_(1) = 0`
`Delta varphi = 0^(@)`
`I_(1) = I_(0) + I_(0) + 2I_(0) cos 0^(@) = 4I_(0)`
`Delta x_(2) = (lambda)/(4)`
`Delta theta = (2pi)/(lambda): (lambda)/(4) = ((pi)/(2))`
`I_(2) = I_(0) + I_(0) + 2I_(0) cos ""(pi)/(2) = 2I_(0)`
`(I_(1))/(I_(2)) = (4I_(0))/(2I_(0)) = (2)/(1)`