1)

Two identical light waves having phase difference 'ϕ' propagate in same direction, when they superpose , the intensity of resultant wave is proportional to 


A) cos2ϕ

B) cos2ϕ2

C) cos2ϕ3

D) cos2ϕ4

Answer:

Option B

Explanation:

For two  coherent sources , the resultant intensity is given as,

lR=l1+l2+2l1l2cosϕ

       Fror two identical light waves,

l1=l2=l

    lR=4lcos2ϕ2

    lRcos2ϕ2