A person riding a car moving at 72 km/h sounds a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing on the road (i) in front of the car (ii) behind the car? Speed of sound in air = 340 m/s.

1250 Hz, 1181 Hz

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1328 Hz, 1181 Hz

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1620 Hz ,1080 Hz

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None of these

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Solution

The correct option is B
1328 Hz, 1181 Hz

i)Given $v_{s}$ = 72 km/hour = 20 m/s, f = 1250
Apparent frequency when car is approaching
a)For second case apparent frequency will be= $(\frac{340 + 0}{340 + 20}) \times 1250 = 1181 H z$

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A person riding a car moving at 72 km/h sounds a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing an the road (a) in front of the car (b) behind the car ? Speed of sound in air = 340 m/s.

Q. A person riding a car moving at 72 km h⁻¹ sound a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing on the road (a) in front of the car (b) behind the car? Speed of sound in air = 340 m s⁻¹.

The horn of a car emits sound with a dominant frequency of 2400 Hz. What will be the apparent dominant frequency heard by a person standing on the road in front of the car if the car is approaching at 18.0 km/h? Speed of sound in air = 340 m/s.

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A person riding a car moving at 72 km/h sounds a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing on the road (i) in front of the car (ii) behind the car? Speed of sound in air = 340 m/s.

The correct option is B 1328 Hz, 1181 Hz i)Given vs = 72 km/hour = 20 m/s, f = 1250 Apparent frequency when car is approaching a)For second case apparent frequency will be=(340+0340+20)×1250=1181Hz

The correct option is B
1328 Hz, 1181 Hz

i)Given $v_{s}$ = 72 km/hour = 20 m/s, f = 1250
Apparent frequency when car is approaching
a)For second case apparent frequency will be= $(\frac{340 + 0}{340 + 20}) \times 1250 = 1181 H z$