Two identical sinusoidal waves each of amplitude 5 mm with a phase difference of `pi//2` are traveling in the same direction in a string. The amplitude of the resultant wave (in mm) is

Options

A. Zero
B. `5sqrt(2)`
C. `5//sqrt(2)`
D. 2.5

Answer

B

Explanation

`A=sqrt(A_(1)^(2)+A_(2)^(2)+2A_(1)A_(2)cosphi)`
`A_(1)=A_(2)=5mm, phi=(pi)/(2)`
`A=sqrt(5^(2)+5^(2)+2xx5xx5xxcos"(pi)/(2))=5sqrt(2)mm`