As shown in figure waves with identical wavelengths and amplitudes and which are intially in phase travel through difference media. Ray 1 travels through air and Ray 2 through a transparent medium for equal length L, in four different situations. Rays reach a common point on the screen. The number of wavelengths in length L is `N_(2)` for Ray 2 and `N_(1)` for Ray 1. In the following table, values of `N_(1)` and `N_(2)` are given for all four situations. The order or the situations according to the intensity of the light at the common point in descending order is Situations
1 2 3 4
`N_(1)` 2.75 1.80 3.00 3.25
`N_(2)` 2.75 2.80 3.25 4.00

Options

A. `I_(3)=I_(4)gtI_(2)gtI_(1)`
B. `I_(1)gtI_(3)=I_(4)gtI_(2)`
C. `I_(1)gtI_(2)gtI_(3)gtI_(4)`
D. `I_(2)gtI_(3)=I_(4)gtI_(1)`

Answer

D

Explanation

Path difference
`Deltax_(1)=(lamda)/(2),Deltax_(2)=lamda,Deltax_(3)=(lamda)/(4),Deltax_(4)=(3lamda)/(4)`
Therefore `I_(2)gtI_(3)=I_(4)I_(1)`