An open tube is in resonance with string (frequency of vibration of the tube is n0). If the tube is dipped in water so that 75% of the length of the tube is inside water, then the ratio of the frequency of tube to string now will be :

(1) 1

(2) 2

(3) $\frac{2}{3}$

(4) $\frac{3}{2}$

Concept Questions :-

Standing waves
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A source of sound of frequency 450 cycles/sec is moving towards a stationary observer with 34 m/sec speed. If the speed of sound is 340 m/sec, then the apparent frequency will be

(1) 410 cycles/sec

(2) 500 cycles/sec

(3) 550 cycles/sec

(4) 450 cycles/sec

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The frequency of a whistle of an engine is 600 cycles/sec is moving with the speed of 30 m/sec towards an observer. The apparent frequency will be (velocity of sound = 330 m/s) [MP PMT 1989]

(1) 600 cps

(2) 660 cps

(3) 990 cps

(4) 330 cps

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An observer moves towards a stationary source of sound of frequency n. The apparent frequency heard by him is 2n. If the velocity of sound in air is 332 m/sec, then the velocity of the observer is :

(1) 166 m/sec

(2) 664 m/sec

(3) 332 m/sec

(4) 1328 m/sec

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A person feels 2.5% difference of frequency of a motor-car horn. If the motor-car is moving to the person and the velocity of sound is 320 m/sec, then the velocity of car will be

(1) 8 m/s (approx.)

(2) 800 m/s

(3) 7 m/s

(4) 6 m/s (approx.)

Concept Questions :-

Doppler effect
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Difficulty Level:

A source of sound emitting a note of frequency 200 Hz moves towards an observer with a velocity v equal to the velocity of sound. If the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is

(1) 50 Hz

(2) 100 Hz

(3) 150 Hz

(4) 200 Hz

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A source of sound is traveling towards a stationary observer. The frequency of the sound heard by the observer is three times the original frequency. The velocity of sound is v m/sec. The speed of the source will be :

(1) $\frac{2}{3}v$

(2) v

(3) $\frac{3}{2}v$

(4) 3v

Concept Questions :-

Doppler effect
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A sound source is moving towards a stationary observer with 1/10 of the speed of sound. The ratio of apparent to real frequency is :

(1) 10/9

(2) 11/10

(3) (11/10)2

(4) (9/10)2

Concept Questions :-

Doppler effect
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Difficulty Level:

The speed of sound in air at a given temperature is 350 m/s. An engine blows whistle at a frequency of 1200 cps. It is approaching the observer with velocity 50 m/s. The apparent frequency in cps heard by the observer will be :

(1) 600

(2) 1050

(3) 1400

(4) 2400

Concept Questions :-

Doppler effect
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Difficulty Level:

The Doppler's effect is applicable for :

(1) Light waves

(2) Sound waves

(3) Space waves

(4) Both (1) and (2)

Concept Questions :-

Doppler effect