Waves NEET Questions with Solutions

Q: How many questions come from Waves in NEET 2027?

You can expect 1 to 2 questions from Waves in NEET 2027. The chapter has high PYQ frequency. Wave speed on a string, frequency of standing waves on strings and in pipes, beats and Doppler effect are the favourites.

Q: What is the wave equation?

A traveling wave moving in the positive x direction is y of x and t equals A sin(omega t minus k x), where A is the amplitude, omega is the angular frequency 2 pi f, and k is the wave number 2 pi over lambda. Wave speed v equals omega over k equals f times lambda.

Q: What is the speed of a wave on a stretched string?

v equals the square root of T over mu, where T is the tension in the string and mu is the linear mass density (mass per unit length, in kg per metre). NEET problems often vary T or change the string and ask how speed changes.

Q: What is the speed of sound in a gas?

Newton gave v equals square root of B over rho, with B the bulk modulus (isothermal). Laplace corrected this to use the adiabatic bulk modulus, giving v equals square root of gamma P over rho, since the rapid compression in a sound wave is closer to adiabatic than isothermal. For air at 0 degrees C this gives 332 m per s, matching observation.

Q: What is the principle of superposition?

When two or more waves overlap in a medium, the resulting displacement at every point is the algebraic sum of the displacements due to each individual wave. This single rule explains interference, beats and standing waves.

Q: What is the Doppler effect?

When source and observer are moving relative to each other, the observed frequency f_obs differs from the emitted frequency f. For sound: f_obs equals f times (v plus minus v_o) over (v plus minus v_s), with appropriate sign conventions. The frequency goes UP when source and observer approach each other and DOWN when they move apart.

Question 1

If n 1 , n 2 and n 3 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 -

Accepted Answer

n 1 = 1 n 1 + 2 n 1 + 3 n 1

Question 2

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

Accepted Answer

6

Question 3

A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36 km/hour. He finds that traffic has eased and a car moving ahead of him at 18 km/hour is honking at a frequency of 1392 Hz. If

Accepted Answer

1412 Hz

Question 4

A source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4 ms−1 at an angle of 60o with th e sourc

Accepted Answer

(2 ) 103 Hz

Question 5

A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequency for this string is:

Accepted Answer

105 Hz

Question 6

A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 ms−1. Then, the frequency of sound that the observer hears in the echo reflected from the clif

Accepted Answer

838 Hz

Question 7

A uniform rope of length L and mass m1, hangs vertically from a rigid support. A block of mass m2 is attached to the free end of the rope. A transverse pulse of wavelength λ1 is produced at the lower

Accepted Answer

√ m1+m2 m2

Question 8

An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuni

Accepted Answer

150 cm

Question 9

Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by th

Accepted Answer

448 Hz

Question 10

The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?

Accepted Answer

20 Hz

Question 11

The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20 cm, the length of the open organ pipe is

Accepted Answer

12·5 cm

Question 12

A tuning fork is used to produce resonance in a glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of 27 ° C two successive resonances are

Accepted Answer

339 m/s

Question 13

In a guitar, two strings A and B made of same material are slightly out of tune and produce beats of frequency 6 Hz. When tension in B is slightly decreased, the beat frequency increases to 7 Hz. If t

Accepted Answer

523 Hz

Question 14

If the initial tension on a stretched string is doubled, then the ratio of the initial and final speeds of a transverse wave along the string is

Accepted Answer

1: 2

Question 15

The ratio of frequencies of fundamental harmonic produced by an open pipe to that of closed pipe having the same length is :

Accepted Answer

2 : 1

Question 16

A pipe open at both ends has a fundamental frequency [math] in air. The pipe is now dipped vertically in a water drum to half of its length. The fundamental frequency of the air column is now equal to

Accepted Answer

[math]

WavesNEET Physics · Class 11 · NCERT Chapter 14

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WavesNEET Physics · Class 11 · NCERT Chapter 14

1NEET 2014Medium4 bookletsIf n 1 , n 2 and n 3 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 -

2NEET 2014Medium4 bookletsThe number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are - (velocity of sound = 340 ms –1 )

5NEET 2015Medium4 bookletsA string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequency for this string is:

6NEET 2016Medium4 bookletsA siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 ms−1. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is : (Take velocity of sound in air = 330 ms−1) www.vedantu.com 3

8NEET 2016Medium4 bookletsAn air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuning fork is:

9NEET 2017Medium5 bookletsTwo cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is [velocity of sound 340 m/s]

10NEET 2017Medium5 bookletsThe two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?

11NEET 2018Medium20 bookletsThe fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20 cm, the length of the open organ pipe is

13NEET 2020Medium24 bookletsIn a guitar, two strings A and B made of same material are slightly out of tune and produce beats of frequency 6 Hz. When tension in B is slightly decreased, the beat frequency increases to 7 Hz. If the frequency of A is 530 Hz, the original frequency of B will be :

14NEET 2022Medium24 bookletsIf the initial tension on a stretched string is doubled, then the ratio of the initial and final speeds of a transverse wave along the string is

15NEET 2023Medium24 bookletsThe ratio of frequencies of fundamental harmonic produced by an open pipe to that of closed pipe having the same length is :

16NEET 2025Medium4 bookletsA pipe open at both ends has a fundamental frequency f in air. The pipe is now dipped vertically in a water drum to half of its length. The fundamental frequency of the air column is now equal to:

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