Two waves having equations
`x_1=asin(omegat+phi_1)`, ` x_2=asin(omegat+phi_2)`
If in the resultant wave the frequency and amplitude remain equal to those of superimposing waves. Then phase difference between them is

Options

A. `pi//6`
B. `2pi//3`
C. `pi//4`
D. `pi//3`

Answer

B

Explanation

`A=sqrt(A_(1)^(2)+A_(2)^(2)+2A_(1)A_(2)cosphi)`
`impliesa^(2)=a^(2)+a^(2)+2a^(2)cosphi`
`cosphi=-(1)/(2)impliesphi=(2pi)/(3)`.