Two waves of same frequency and same amplitude from two monochromatic sources are allowed to superpose at a certain point. If in one case the phase difference is 0 and in other case it is `pi//2` then the ratio of the intensities in the two cases will be

Options

A. `1:1`
B. `2:1`
C. `4:1`
D. None of these

Answer

B

Explanation

Case I, Resultant amplitude `A_(1)=2A`
`therefore I_(1)=4I`
Case II, Resultant amplitude
`A_(2)=sqrt(2)A rArr I_(2)=2I rArr (I_(1))/(I_(2))=(2)/(1)`