An Indian submarine and an enemy submarine move towards each othe… - Vidyadip

MCQ

An Indian submarine and an enemy submarine move towards each other during maneuvers in motionless water in the Indian ocean. The Indian submarine moves at $50 km/h$, and the enemy submarine at $70 km/h$. The Indian sub sends out a sonar signal (sound wave in water) at $1000 Hz$. Sonar waves travel at $5500 km/h$. What is the frequency detected by the Indian submarine .... $kHz$

✓
$1.02$
B
$2$
C
$2.5$
D
$4.7$

✓

Answer

Correct option: A.

$1.02$

a
(a) Frequency detected by Indian submarine

$n' = n\,\left[ {\frac{{v + {v_{sub}}}}{{v - {v_{sub}}}}} \right] = 1000\,\left[ {\frac{{5500 + 50}}{{5500 - 50}}} \right] \approx 1.02\,kHz.$

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