Two waves of equal amplitude and frequency interfere each other. The ratio of intensity when the two waves arrive in phase to that when they arrive `90^@` out of phase is

Options

A. (a) `1:1`
B. (b) `sqrt2:1`
C. (c) `2:1`
D. (d) `4:1`

Answer

C

Explanation

Resultant intensity `I=4I_0cos^2(varphi//2)`
`impliesI_1/I_2=(cos^2(varphi_1//2))/(cos^2(varphi_2//2))=(cos^20)/(cos^2(90//2))=2/1`