A bat emits ultrasonic waves of frequency 39 kHz and receives and echo 0.2 s later. If the speed of sound in air is 300 m/s and the speed of electro magnetic waves `3 xx 10^(8) m//s` then the distance of the bat from the object producing the echo is

Options

A. 60 m
B. 30 m
C. `3 xx 10^(7) m`
D. `3 xx 10^(6) m`

Answer

B

Explanation

`2x = v t = 300 xx 0.2 = 60 m`