If n1, n2 and n3 are, are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by

(a) 1/n=1/n1+1/n2+1/n3

(b) 1/√n=1/√n1+1/√n2+1/√n3

(c) √n=√n1+√n2+√n3

(d) n=n1+n2+n3

Concept Questions :-

Travelling wave on string
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The number of possible natural oscillations of the air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are (velocity of sound 340ms-1) :

(a)4

(b)5

(c)7

(d)6

Concept Questions :-

Wave motion
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36km/h. He finds that traffic has eased and a car moving ahead of him at 18km/h is honking at a frequency of 1392Hz. If the speed of sound is 343m/s, the frequency of the honk as heard by him will be

(a)1332Hz

(b)1372Hz

(c)1412Hz

(d)1454Hz

Concept Questions :-

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

Difficulty Level:

A wave travelling in the positive x-direction having maximum displacement along y-direction as 1m, wavelength 2π m and frequency of 1/π Hz is represented by

(a) y=sin(x-2t)

(b) y=sin(2πx-2πt)

(c) y=sin(10πx-20πt)

(d) y=sin(2πx+2πt)

Concept Questions :-

Types of waves
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Difficulty Level:

If we study the vibration of a pipe open at both ends. then the following statements is not true

(a) Open end will be anti-node

(b) Odd harmonics of the fundamental frequency will be generated

(c) All harmonics of the fundamental frequency will be generated

(d) Pressure change will be maximum at both ends

Concept Questions :-

Standing waves
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Difficulty Level:

A source of unknown frequency gives 4 beats/s when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second when sounded with a source of frequency 513 Hz. The unknown frequency is

(a) 254 Hz (b) 246 Hz (c) 240 Hz (d) 260 Hz

Concept Questions :-

Beats
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Difficulty Level:

When a string is divided into three segments of lengths  the fundamental frequencies of these three segments are  respectively. The original fundamental frequency (v) of the string is

(a) $\sqrt{v}=\sqrt{{v}_{1}}+\sqrt{{v}_{2}}+\sqrt{{v}_{3}}$

(b) $v={v}_{1}+{v}_{2}+{v}_{3}$

(c) $\frac{1}{v}=\frac{1}{{v}_{1}}+\frac{1}{{v}_{2}}+\frac{1}{{v}_{3}}$

(d) $\frac{1}{\sqrt{v}}=\frac{1}{\sqrt{{v}_{1}}}+\frac{1}{\sqrt{{v}_{2}}}+\frac{1}{\sqrt{{v}_{3}}}$

Concept Questions :-

Travelling wave on string
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Two sources of sound placed close to each other, are emitting progressive waves given by

${\mathrm{y}}_{1}$=4 sin 600$\mathrm{\pi t}$ and ${\mathrm{y}}_{2}$=5 sin 608 $\mathrm{\pi t}$

An observer located near these two sources of sound will hear

(a)4 beats per second with intensity ratio 25:16 between waxing and waning

(b) 8 beats per second with intensity ratio 25:16 between waxing and waning

(c) 8 beats per second with intensity ratio 81:1 between waxing and waning

(d) 4 beats per second with intensity ratio 81:1 waxing and waning

Concept Questions :-

Beats
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The equation of a simple harmonic wave is

given by

where x and y are in meters and t is in

seconds. The ratio of maximum particle

velocity to the wave velocity is

(a) $2\mathrm{\pi }$

(b) $\frac{3}{2}\mathrm{\pi }$

(c) $3\mathrm{\pi }$

(d) $\frac{2}{3}\mathrm{\pi }$

Concept Questions :-

Speed of sound
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A train moving at a speed of 220 ${\mathrm{ms}}^{-1}$

towards a stationary object, emits a sound

of frequency 1000 Hz. Some of the sound

reaching the object gets reflected back to

the train as echo. The frequency of the echo

as detected by the driver of the train is

(speed of sound in air is 330 ${\mathrm{ms}}^{-1}$)

(a) 3500Hz

(b) 4000Hz

(c) 5000Hz

(d) 3000Hz

Concept Questions :-

Doppler effect