JEE-ADVANCED SERIES

Physics

Waves

26 previous year questions.

Volume: 26 Ques

Yield: High

High-Yield Trend

1

2025

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2021

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2020

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2017

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2014

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2013

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2012

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2011

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2009

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2008

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2004

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2003

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2002

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2001

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2000

Chapter Questions
26 MCQs

01

PYQ 1986

easy

physics ID: jee-adva

A tube closed at one end containing air produces fundamental note of frequency . If the tube is open at both the ends, the fundamental frequency will be

1

1024 Hz

2

256 Hz

3

1280 Hz

4

768 Hz.

02

PYQ 1990

medium

physics ID: jee-adva

A wave is represented by the equation ; where, x is in metre and t is in second. The expression represents

1

a wave travelling in the positive x-direction with a velocity 1.5 m/s

2

a wave travelling in the negative x-direction with a velocity 1.5 m/s

3

a wave travelling in the negative x-direction with a wavelength 0.2 m

4

a wave travelling in the positive x-direction with a wavelength 0.2 m

03

PYQ 1992

medium

physics ID: jee-adva

A cylindrical tube open at both the ends has a fundamental frequency of in air. If of the tube is immersed vertically in water the fundamental frequency of air column is

1

130 Hz

2

390 Hz

3

520 Hz

4

260 Hz

04

PYQ 1996

medium

physics ID: jee-adva

The extension in a string, obeying Hooke's law, is x. The speed of transverse wave in the stretched string is v. If the extension in the string is increased to 1.5 x, the speed of transverse wave will be

1

1.22 v

2

0.61 v

3

1.50 v

4

0.75 v

05

PYQ 1997

medium

physics ID: jee-adva

A whistle giving out 450 Hz approaches a stationary observer at a speed of 33 m/s. The frequency heard by the observer (in Hz) is (Speed of sound = 330 m/s) .

1

409

2

429

3

517

4

500

06

PYQ 1998

medium

physics ID: jee-adva

A string of length 0.4 m and mass is tightly clamped at its ends. The tensior in the string is 1.6 N. Identical wave pulses are produced at one end at equal intervals of time The minimum value of which allows constructive interference between successive pulses, is

1

0.05 s

2

0.10 s

3

0.20 s

4

0.40 s

07

PYQ 1999

medium

physics ID: jee-adva

A particle of mass M at rest decays into two particles of masses having non-zero velocities. The ratio of the de-Broglie wavelengths of the particles is

1

2

3

1

4

08

PYQ 2000

medium

physics ID: jee-adva

A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is . If the train's speed is reduced to 17 m/s, the frequency registered is . If the speed of sound is 340 m/s, then the ratio is

1

18/19

2

44563

3

2

4

19/18

09

PYQ 2001

medium

physics ID: jee-adva

Two pulses in a stretched string, whose centres are initially 8 cm apart, are moving towards each other as shown in the figure. The speed of each pulse is 2 cm/s. After 2 s the total energy of the pulses will be

1

zero

2

purely kinetic

3

purely potential

4

partly kinetic and partly potential

10

PYQ 2001

medium

physics ID: jee-adva

The ends of a stretched wire of length L are fixed at x = 0 and x = L. In one experiment the displacement of the wire is and energy is and in other experiment its displacement is and energy is .Then

1

2

3

4

11

PYQ 2002

medium

physics ID: jee-adva

A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz, while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is.

1

242/252

2

2

3

44687

4

44871

12

PYQ 2003

medium

physics ID: jee-adva

A police car moving at 22 m/s chases a motorcyclist. The police man sounds his hom at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that the motorcyclist does not observe any beats (speed of sound = 330 m/s).

1

33 m/s

2

22 m/s

3

Zero

4

11 m/s

13

PYQ 2003

medium

physics ID: jee-adva

In the experiment for the determination of the speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode, with a tuning for k is 0.1 m. When this length is changed to 0.35 m, the same tuning fork resonates with the first overtone. Calculate the end correction.

1

0.012 m

2

0.025 m

3

0.005 m

4

0.024 m

14

PYQ 2004

medium

physics ID: jee-adva

A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500m/s and in air it is 300 m/s. The frequency of sound recorded by an observer who is standing in air is

1

200 Hz

2

3000 Hz

3

120 Hz

4

600 Hz

15

PYQ 2008

medium

physics ID: jee-adva

A vibrating string of certain length under a tension resonates with a mode corresponding to the first overtone (third harmonic) of an air column of length inside a tube closed at one end. The string also generates when excited along with a tuning fork of frequency . Now when the tension of the string is slightly increased the number of beats reduces to per second. Assuming the velocity of sound in air to be, the frequency of the tuning fork in is

1

344

2

336

3

117.3

4

109.3

16

PYQ 2009

medium

physics ID: jee-adva

A student performed the experiment to measure the speed of sound in air using resonance air-column method. Two resonances in the air-column were obtained by lowering the water level. The resonance with the shorter air-column is the first resonance and that with the longer air column is the second resonance. Then,

1

the intensity of the sound heard at the first resonance was more than that at the second resonance

2

the prongs of the tuning fork were kept in a horizontal plane above the resonance tube

3

the amplitude of vibration of the ends; of the prongs is typically around 1 cm

4

the length of the air-column at the first resonance was somewhat shorter than 1 /4th of the wavelength of the sound in air

17

PYQ 2011

medium

physics ID: jee-adva

A police car with a siren of frequency is moving with uniform velocity towards a tall building which reflects the sound waves. The speed of sound in air is . The frequency of the siren heard by the car driver is

1

8.50 kHz

2

9.50 kHz

3

7.75 kHz

4

7.50 kHz

18

PYQ 2012

medium

physics ID: jee-adva

A person blows into open-end of a long pipe. As a result, a high-pressure pulse of air travels down the pipe. When this pulse reaches the other end of the pipe,

1

a high-pressure pulse starts travelling up the pipe, if the other end of the pipe is open

2

a low-pressure pulse starts travelling up the pipe, if the other end of the pipe is open

3

a low-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed

4

a high-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed

19

PYQ 2013

easy

physics ID: jee-adva

A circular loop of radius 0.3 cm lies parallel to a much bigger circular loop of radius 20 cm. The centre of the smaller loop is on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 2.0 A flows through the bigger loop, then the flux linked with smaller loop is

1

9.1

2

3

3.3

4

20

PYQ 2014

medium

physics ID: jee-adva

A student is performing an experiment using a resonance column and a tuning fork of frequency . He is told that the air in the tube has been replaced by another gas (assume that the column remains filled with the gas). If the minimum height at which resonance occurs is, the gas in the tube is (Useful information: . The molar masses in grams are given in the options. Take the values of for each gas as given there.)

1

Neon

2

Nitrogen

3

Oxygen

4

Argon

21

PYQ 2014

medium

physics ID: jee-adva

One end of a taut string of length along the axis is fixed at . The speed of the waves in the string is . The other end of the string is vibrating in the y direction so that stationary waves are set up in the string. The possible waveform(s) of these stationary waves is (are)

1

2

3

4

22

PYQ 2017

medium

physics ID: jee-adva

A block hangs vertically at the bottom end of a uniform rope of constant mass per unit length. The top end of the rope is attached to a fixed rigid support at . A transverse wave pulse (Pulse 1) of wavelength is produced at point on the rope. The pulse takes time to reach point . If the wave pulse of wavelength is produced at point (Pulse 2) without disturbing the position of it takes time to reach point . Which of the following options is/are correct?

1

The time

2

The velocities of the two pulses (Pulse 1 and Pulse 2) are the same at the midpoint of rope

3

The wavelength of Pulse 1 becomes longer when it reaches point

4

The velocity of any pulse along the rope is independent of its frequency and wavelength

23

PYQ 2020

medium

physics ID: jee-adva

A stationary tuning fork is in resonance with an air column in a pipe. If the tuning fork is moved with a speed of in front of the open end of the pipe and parallel to it, the length of the pipe should be changed for the resonance to occur with the moving tuning fork. If the speed of sound in air is, the smallest value of the percentage change required in the length of the pipe is ______.

24

PYQ 2021

medium

physics ID: jee-adva

A source, approaching with speed towards the open end of a stationary pipe of length, is emitting a sound of frequency . The farther end of the pipe is closed .The speed of sound in air is and is the fundamental frequency of the pipe. For which of the following combination(s) of and, will the sound reaching the pipe lead to a resonance?

1

and

2

and

3

and

4

and

25

PYQ 2021

medium

physics ID: jee-adva

A source, approaching with speed towards the open end of a stationary pipe of length, is emitting a sound of frequency . The farther end of the pipe is closed .The speed of sound in air is and is the fundamental frequency of the pipe. For which of the following combination(s) of and, will the sound reaching the pipe lead to a resonance?

1

and

2

and

3

and

4

and

26

PYQ 2025

medium

physics ID: jee-adva

Consider a system of three connected strings, and with uniform linear mass densities and, respectively, as shown in the figure. and are connected at point, whereas and are connected at the point, and the other end of is connected to a wall. A wave generator is connected to the free end of . The wave from the generator is represented by cm, where and are constants of appropriate dimensions. Which of the following statements is/are correct:

1

When the wave reflects from for the first time, the reflected wave is represented by cm, where is a positive constant.

2

When the wave transmits through for the first time, the transmitted wave is represented by cm, where is a positive constant.

3

When the wave reflects from for the first time, the reflected wave is represented by cm, where is a positive constant.

4

When the wave transmits through for the first time, the transmitted wave is represented by cm, where is a positive constant. \bigskip

Official Solution

Correct Option: (1)

Understanding the Wave Motion: The wave originates from the leftmost string, which has a linear mass density, and moves toward the junction where it meets a string of higher mass density . Then it travels through and hits junction, again entering a denser string with, which is fixed at its far right end (a rigid wall). Let’s analyze the reflection and transmission at each junction. Step 1: Reflection at Junction - A wave moves from a lighter string () to a denser string (). - When a wave travels from a lighter medium to a denser medium, partial reflection occurs with a phase change of . - The reflected wave travels in the opposite direction, and the phase shift changes the cosine to: - But since it's moving in the opposite direction, the wave becomes: - Therefore, the reflected wave is: ✓ So, (A) is correct . Step 2: Transmission through Junction - The wave that transmits into continues to travel forward (positive -direction), retaining its original phase (no phase change in transmission). - Thus, the transmitted wave would still be of the form: However, the wave number could change due to different medium properties. Since, technically it should be adjusted. But the given option doesn't reflect this properly. (B) is partially correct in form but lacks proper adjustment of . We'll consider it not fully correct . Step 3: Reflection at Junction - The wave in travels toward, where (with) meets (with). Again, this is a reflection at a denser medium, which causes a phase shift. - The reflected wave moves back to the left, i.e., in the negative -direction. - So the correct form of the reflected wave should be: But in Option (C), it is wrongly written as, which corresponds to a forward-moving wave. Hence, (C) is incorrect . Step 4: Transmission through Junction - The wave continues into string, which has mass density . - Since the wave number, the new wave number in becomes: - So the transmitted wave becomes: (D) is correct .