Question

A bat emits an ultrasonic sound wave at $33.0\, kHz$ and receives an echo $0.1\, s$ later. What is the distance of the bat from the object-producing echo? (Speed of sound in air is $330\, m/s$)

• A. 10.0 m
• B. 20.0 m
• C. 33.0 m
• D. 66.0 m
• E. 16.5 m

Answer 1

Answer: (E)

Given, time in which an echo is received $=0.1\, s$
and speed of sound in air $=330\,m / s$
Since, the echo received by bat travelled a distance double to the distance between bat and object.
$\therefore 2 D=v \times$ ( time )
where, $D=$ distance between bat and object and $v=$ speed of sound
$\Rightarrow D =\frac{v \times \text{time} }{2}=\frac{330 \times 0.1}{2} $
$=16.5\,m$