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A sonar pulse sent from a ship hits a submarine and returns after 0.90 s. Speed of sound in seawater is 1530 m/s. The distance to the submarine is:

A1530 m
B688.5 m
C1377 m
D344 m
Answer & Solution
Correct answer: B. 688.5 m
The pulse goes to the submarine and back in 0.90 s — so one-way time is 0.45 s. Distance = speed × time = 1530 m/s × 0.45 s = 688.5 m. SONAR (Sound Navigation and Ranging) uses this principle to locate underwater objects, exactly as bats do above water.
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