alleryA bat emits an ultrasonic pulse at 60 kHz. After 0.04 s, it hears the echo. How far is the obstacle? (Speed of sound = 340 m/s)
A27.2 m
B68 m
C6.8 m
D13.6 m
Answer & Solution
Correct answer: C. 6.8 m
Total round-trip distance = 340 × 0.04 = 13.6 m.
The obstacle is HALF this distance (round trip = there + back).
Distance to obstacle = 13.6 / 2 = 6.8 m.
This is how bats use echolocation.
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