A bat moving at 1`0 ms^(-1)` towards a wall sends a sound signal of 8000 Hz towards it. On reflection it hears a sound of frequency f. The value of g in Hz is close to (speed to sound `= 320 ms^(-1)`) :-

Options

A. 8516
B. 8258
C. 8424
D. 8000

Answer

A

Explanation

Reflected frequency of sound reaching bat
`[[V-(-V_0))/(V-V_s)]f=[(V+V_0)/(V-V_s)]f=(V+10)/(V-10)f`
`=((320+10)/(320-10))times8000=8516 Hz`