Question

Two sound waves travel out from a common point have frequencies 30 Hz and 40 Hz respectively. Calculate the phase difference between them after 0.8 second?

• A. Zero
• B. $\frac{\Pi }{4}$
• C. $\frac{5\Pi }{2}$
• D. $5\Pi$

Answer 1

The correct option is A Zero

No. of oscillation that wave 1 (f=30hz) has taken in 0.8 second = 24

No. of oscillation that wave 2 (f=40hz) has taken in 0.8 second = 32

So after 0.8 second both of them will be at initial point of oscillating loop. Thus phase difference = 0