What is a wave in physics?

A wave is a disturbance that propagates through a medium or space and transfers energy without causing any permanent displacement of matter.

Wave motion is the propagation of oscillations from one point to another in a medium due to restoring forces and inertia of particles.

Does wave motion involve transfer of matter?

No, wave motion involves transfer of energy only; particles oscillate about their mean positions.

What are mechanical waves?

Mechanical waves are waves that require a material medium for propagation, such as sound waves and water waves.

What are non-mechanical waves?

Non-mechanical waves do not require a material medium and can propagate through vacuum, for example electromagnetic waves.

What are transverse waves?

Transverse waves are waves in which particles of the medium oscillate perpendicular to the direction of wave propagation.

Give examples of transverse waves.

Waves on a stretched string, ripples on the surface of water, and electromagnetic waves are examples.

What are longitudinal waves?

Longitudinal waves are waves in which particles of the medium oscillate parallel to the direction of wave propagation.

Give examples of longitudinal waves.

Sound waves in air and compression waves in solids are examples of longitudinal waves.

What is the wavelength of a wave?

Wavelength is the distance between two successive points in the same phase of vibration, such as consecutive crests or compressions.

What is the SI unit of wavelength?

The SI unit of wavelength is metre (m).

What is frequency of a wave?

Frequency is the number of complete oscillations made by a particle of the medium per second.

What is the SI unit of frequency?

The SI unit of frequency is hertz (Hz).

What is the time period of a wave?

Time period is the time taken by a particle of the medium to complete one full oscillation.

How are frequency and time period related?

Frequency is the reciprocal of time period, given by \( f = \frac{1}{T} \).

Waves PYQs: JEE & NEET Previous Year Questions (Class 11 Physics)

Q1

A wave on a stretched string is represented by \( y = 0.02 \sin(4\pi x - 200\pi t) \). The speed of the wave is
(Exam: IIT-JEE Year: 1998)

(A) \(25\,\text{m s}^{-1}\)

(B) \(50\,\text{m s}^{-1}\)

(C) \(100\,\text{m s}^{-1}\)

(D) \(200\,\text{m s}^{-1}\)

Q2

The ratio of maximum particle velocity to wave velocity in a transverse wave is
(Exam: NEET Year: 2019)

(A) \(A\)

(B) \(kA\)

(C) \(\omega A\)

(D) \(\frac{A}{\lambda}\)

Q3

In a stationary wave, the distance between a node and the adjacent antinode is
(Exam: AIIMS Year: 2014)

(A) \(\frac{\lambda}{2}\)

(B) \(\frac{\lambda}{4}\)

(C) \(\lambda\)

(D) \(\frac{3\lambda}{4}\)

Q4

The fundamental frequency of a stretched string fixed at both ends is \(f\). The frequency of the third harmonic is
(Exam: IIT-JEE Year: 2003)

(A) \(2f\)

(B) \(3f\)

(C) \(4f\)

(D) \(6f\)

Q5

Sound waves cannot be polarized because they are
(Exam: NEET Year: 2016)

(A) Longitudinal

(B) Transverse

(C) Mechanical

(D) Electromagnetic

Q6

Two waves of same frequency interfere. The condition for destructive interference is
(Exam: JEE Main Year: 2021)

(A) Path difference \(n\lambda\)

(B) Path difference \((2n+1)\lambda\)

(C) Path difference \(\frac{(2n+1)\lambda}{2}\)

(D) Path difference \(\frac{n\lambda}{2}\)

Q7

The speed of sound in air increases with
(Exam: NEET Year: 2020)

(A) Increase in humidity

(B) Increase in pressure

(C) Decrease in temperature

(D) Increase in density

Q8

In a stretched string, wave speed depends on
(Exam: IIT-JEE Year: 2001)

(A) Amplitude

(B) Frequency

(C) Tension and linear density

(D) Length of string

Q9

A tuning fork produces resonance in a resonance tube when the air column length is
(Exam: AIIMS Year: 2011)

(A) \(\frac{\lambda}{4}\)

(B) \(\frac{\lambda}{2}\)

(C) \(\frac{3\lambda}{4}\)

(D) Both a and c

Q10

Beats are produced due to difference in
(Exam: BITSAT Year: 2018)

(A) Amplitude

(B) Phase

(C) Frequency

(D) Wavelength

Q11

A source of sound approaches a stationary observer with speed \(u\). The apparent frequency heard is
(Exam: IIT-JEE Year: 2006)

(A) \(f\left(1+\frac{u}{v}\right)\)

(B) \(f\left(1-\frac{u}{v}\right)\)

(C) \(\frac{fv}{v+u}\)

(D) \(\frac{fv}{v-u}\)

Q12

In a standing wave, the points where displacement is always zero are called
(Exam: NEET Year: 2017)

(A) Antinodes

(B) Crests

(C) Nodes

(D) Troughs

Q13

The fundamental frequency of an open organ pipe of length \(L\) is
(Exam: AIIMS Year: 2010)

(A) \(\frac{v}{4L}\)

(B) \(\frac{v}{2L}\)

(C) \(\frac{v}{L}\)

(D) \(\frac{2v}{L}\)

Q14

The intensity of a wave is proportional to
(Exam: JEE Main Year: 2020)

(A) Amplitude

(B) Frequency

(C) Square of amplitude

(D) Wavelength

Q15

Two waves of equal amplitude interfere destructively. Resultant intensity is
(Exam: IIT-JEE Year: 1995)

(A) Zero

(B) Half

(C) Double

(D) Same as one wave

Q16

Phase difference between two successive nodes in a stationary wave is
(Exam: KVPY Year: 2013)

(A) \(0\)

(B) \(\pi\)

(C) \(\frac{\pi}{2}\)

(D) \(2\pi\)

Q17

The speed of sound in a gas is independent of
(Exam: NEET Year: 2015)

(A) Temperature

(B) Density

(C) Pressure (at constant temperature)

(D) Humidity

Q18

If tension in a stretched string is quadrupled, wave speed becomes
(Exam: IIT-JEE Year: 2008)

(A) Half

(B) Double

(C) Four times

(D) Same

Q19

The number of beats per second produced by two tuning forks of frequencies 256 Hz and 260 Hz is
(Exam: BITSAT Year: 2019)

(A) 2

(B) 4

(C) 6

(D) 16

Q20

In a closed pipe, only which harmonics are present?
(Exam: NEET Year: 2021)

(A) Even

(B) Odd

(C) All

(D) Prime

Q21

The ratio of wavelength of fundamental note in closed pipe to open pipe of same length is
(Exam: IIT-JEE Year: 2004)

(A) 1:1

(B) 2:1

(C) 1:2

(D) 4:1

Q22

Doppler effect is observed only when
(Exam: AIIMS Year: 2012)

(A) Source moves

(B) Observer moves

(C) Medium moves

(D) There is relative motion

Q23

The energy transported by a wave depends on
(Exam: JEE Main Year: 2019)

(A) Frequency only

(B) Amplitude only

(C) Amplitude and frequency

(D) Wavelength only

Q24

Group velocity is given by
(Exam: IIT-JEE Year: 2002)

(A) \(\frac{\omega}{k}\)

(B) \(\frac{d\omega}{dk}\)

(C) \(vk\)

(D) \(\frac{dk}{d\omega}\)

Q25

Phase velocity of a wave is
(Exam: KVPY Year: 2015)

(A) Particle velocity

(B) Velocity of energy transport

(C) Velocity of wave crest

(D) Zero

Q26

A wave reflects from a rigid boundary with phase change of
(Exam: NEET Year: 2018)

(A) \(0\)

(B) \(\pi\)

(C) \(\frac{\pi}{2}\)

(D) \(2\pi\)

Q27

End correction is applied because
(Exam: AIIMS Year: 2011)

(A) Pipe walls vibrate

(B) Air vibrates outside the pipe

(C) Pipe length changes

(D) Sound leaks

Q28

Speed of sound is maximum in
(Exam: NEET Year: 2014)

(A) Solids

(B) Liquids

(C) Gases

(D) Vacuum

Q29

If frequency of wave doubles, its wavelength becomes
(Exam: IIT-JEE Year: 1999)

(A) Same

(B) Double

(C) Half

(D) Four times

Q30

A wave carries
(Exam: JEE Main Year: 2022)

(A) Matter

(B) Energy

(C) Medium

(D) Mass

Q31

Standing waves are formed due to
(Exam: IIT-JEE Year: 2007)

(A) Refraction

(B) Diffraction

(C) Interference

(D) Polarization

Q32

Distance between two successive antinodes is
(Exam: NEET Year: 2016)

(A) \(\lambda\)

(B) \(\frac{\lambda}{2}\)

(C) \(\frac{\lambda}{4}\)

(D) \(2\lambda\)

Q33

The wave equation represents
(Exam: IIT-JEE Year: 2000)

(A) SHM

(B) Progressive wave

(C) Standing wave

(D) Circular motion

Q34

If linear density of string increases, wave speed
(Exam: JEE Main Year: 2021)

(A) Increases

(B) Decreases

(C) Remains same

(D) Becomes zero

Q35

Maximum displacement occurs at
(Exam: NEET Year: 2013)

(A) Node

(B) Antinode

(C) Midpoint

(D) Fixed end

Q36

Sound intensity level is measured in
(Exam: AIIMS Year: 2009)

(A) Hertz

(B) Decibel

(C) Joule

(D) Pascal

Q37

The phenomenon responsible for hearing a sound around a corner is
(Exam: NEET Year: 2019)

(A) Reflection

(B) Refraction

(C) Diffraction

(D) Interference

Q38

Phase difference between displacement and velocity in SHM is
(Exam: IIT-JEE Year: 1997)

(A) \(0\)

(B) \(\frac{\pi}{2}\)

(C) \(\pi\)

(D) \(2\pi\)

Q39

Which wave property changes on reflection?
(Exam: KVPY Year: 2014)

(A) Frequency

(B) Speed

(C) Phase

(D) Wavelength

Q40

The loudness of sound depends on
(Exam: NEET Year: 2012)

(A) Frequency

(B) Wavelength

(C) Intensity

(D) Speed

Q41

Which of the following is not a mechanical wave?
(Exam: IIT-JEE Year: 2005)

(A) Sound wave

(B) Water wave

(C) Light wave

(D) Seismic wave

Q42

A wave travelling in opposite direction is represented by
(Exam: JEE Main Year: 2020)

(A) \(kx-\omega t\)

(B) \(kx+\omega t\)

(C) \(\omega t-kx\)

(D) Both b and c

Q43

Which factor does not affect speed of sound in air?
(Exam: NEET Year: 2011)

(A) Temperature

(B) Humidity

(C) Density

(D) Amplitude

Q44

Beats are heard clearly when frequency difference is
(Exam: IIT-JEE Year: 1996)

(A) Very large

(B) Very small

(C) Zero

(D) Infinite

Q45

In stationary waves, energy transfer is
(Exam: AIIMS Year: 2013)

(A) Maximum

(B) Minimum

(C) Zero

(D) Variable

Q46

Phase difference between two points separated by \(\lambda\) is
(Exam: NEET Year: 2018)

(A) \(0\)

(B) \(\pi\)

(C) \(2\pi\)

(D) \(\frac{\pi}{2}\)

Q47

Which wave phenomenon explains echo?
(Exam: JEE Main Year: 2017)

(A) Diffraction

(B) Refraction

(C) Reflection

(D) Interference

Q48

The pitch of sound depends on
(Exam: NEET Year: 2015)

(A) Amplitude

(B) Frequency

(C) Speed

(D) Intensity

Q49

A string fixed at one end and free at the other supports
(Exam: IIT-JEE Year: 2009)

(A) All harmonics

(B) Even harmonics

(C) Odd harmonics

(D) No harmonics

Q50

Which condition is necessary for interference?
(Exam: Olympiad Year: 2016)

(A) Same amplitude

(B) Same phase

(C) Coherent sources

(D) Same speed

Class 11 Physics – Waves

PYQs Overview

Key Formulas

Study Strategy

Topic Frequency in Waves PYQs

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