NEET PhysicsUpdated 19 Oct 2026

Waves: NEET PYQs and weightage

Waves carries 2.9 of 100 Physics marks in NEET by past-paper share: 22 of the 758 tagged NEET Physics PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 19 of 30 Physics chapters.

Take the 25-question Waves test Formula sheet ↓All NEET Physics chapters

2.9/100 Weight in Physics

Exam importance (3/5, by past-paper share)

22 NEET PYQs

347 Practice questions

274 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Physics PYQs in the bank (22 of 758), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Waves: formula sheet for NEET

14 formulas, each with when to use it. Copy it onto one page of your notebook: that page is this chapter's handbook.

Wave speed
$v = ν λ = \frac{ω}{k}$
Use it when: You have any two of speed, frequency, wavelength (or $ω$ and $k$ ) and need the third.
Wave number and angular frequency
$k = \frac{2 π}{λ}$
$ω = \frac{2 π}{T} = 2 π ν$
Use it when: Reading $λ$ , $T$ or $ν$ off a wave equation ( $k$ is in rad m $^{- 1}$ , not m).
Progressive wave
$y (x, t) = a sin (k x - ω t + ϕ)$
Use it when: A wave moves along $+ x$ ; with $(k x + ω t)$ it moves along $- x$ .
Transverse wave on a string
$v = \frac{T}{μ}$
$μ = \frac{m}{L}$
Use it when: A string or wire has a given tension; $μ$ is mass per unit length in kg m $^{- 1}$ .
Longitudinal wave in a fluid
$v = \frac{B}{ρ}$
Use it when: Sound travels in a liquid or gas and the bulk modulus is given.
Longitudinal wave in a solid rod
$v = \frac{Y}{ρ}$
Use it when: Sound travels along a thin bar or rod and Young's modulus is given.
Speed of sound in a gas (Laplace)
$v = \frac{γ P}{ρ}$
Use it when: Finding sound speed in a gas; Newton's $P / ρ$ assumes isothermal changes and gives about $280 m s^{- 1}$ for air, roughly 15% too low.
Two equal waves in the same direction
$A = 2 a cos \frac{ϕ}{2}$
Use it when: Two waves of the same $a$ , $ω$ , $k$ differ only by phase $ϕ$ ( $ϕ = 0$ gives $2 a$ , $ϕ = π$ gives $0$ ).
Standing wave
$y = 2 a sin k x cos ω t$
$nodes at x = \frac{nλ}{2}$
$antinodes at x = (n + \frac{1}{2}) \frac{λ}{2}$
Use it when: Two identical waves travel in opposite directions; node to node (or antinode to antinode) is $λ /2$ .
String fixed at both ends
$ν_{n} = \frac{n v}{2 L} (n = 1, 2, 3, \dots)$
$ν_{1} = \frac{1}{2 L} \frac{T}{μ}$
Use it when: Finding harmonics of a sonometer wire or sitar string (all harmonics present).
Pipe open at both ends
$ν_{n} = \frac{n v}{2 L} (n = 1, 2, 3, \dots)$
Use it when: Both ends of the air column are open (antinodes); all harmonics present.
Pipe closed at one end
$ν = \frac{( 2 n + 1 ) v}{4 L} (n = 0, 1, 2, \dots)$
Use it when: One end is closed (node) and one open; fundamental is $v /4 L$ , then $3 v /4 L$ , $5 v /4 L$ .
Beats
$ν_{beat} = ∣ ν_{1} - ν_{2} ∣$
Use it when: Two close frequencies sound together; check whether loading or tension change raises or lowers the beat count.
Reflection phase
$rigid end \to phase change π, y_{r} = - a sin (k x + ω t)$
$free/open end \to no phase change$
Use it when: Writing the reflected wave at a fixed wall versus a free ring or open pipe end.

Trap

A pipe closed at one end has only odd harmonics. After the fundamental v/4L, the next resonance is 3v/4L, not 2v/4L. Students who take a source frequency as the closed pipe's 2nd or 4th harmonic predict a resonance that never happens.

How does NEET ask Waves?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1PhysicsNEET UG PYQStanding Waves and Normal Modes

Try right here · No sign-in

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?

Answer key (D) & worked solution

Correct answer: Option D

Two successive frequencies of closed pipe

\frac{n v}{4 l} = 220

… (i)

\frac{( n + 2 ) v}{4 l} = 260

… (ii) Dividing (ii) by (i), we get

\frac{n + 2}{n} = \frac{260}{220} = \frac{13}{11}

11 n + 22 = 13 n

n = 11

So,

11 \frac{v}{4 l} = 220

\frac{v}{4 l} = 20

So fundamental frequency is 20 Hz.

Q2PhysicsNEET UG PYQStanding Waves and Normal Modes

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

AOpen end will be node of pressure wave

BOdd harmonics of the fundamental frequency will be generated

CAll harmonic of the fundamental frequency will be generated

DPressure change will be maximum at both ends

Answer key (D) & worked solution

Correct answer: Option D

In case of the vibration of a pipe open at both ends, the air column can vibrate in several different nodes subjected to the boundary condition that there must be a node of pressure wave at its open end. Hence, option (1) is correct. Ratio of frequency is v : 2v : 3v : 4v : 5v Where

v = \frac{V}{2 L}

Both odd and even harmonic will be present. Hence option (1), (2) and (3) are correct. The pressure variation is minimum at node of pressure wave. Hence option (4) is incorrect.

Q3PhysicsNEET UG PYQStanding Waves and Normal Modes

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

^{o}

C two successive resonances are produced at 20 cm and 73 cm of column length. If the frequency of the tuning fork is 320 Hz, the velocity of sound in air at

2 7^{o} C

A350 m/s

B339 m/s

C330 m/s

D300 m/s

Answer key (B) & worked solution

Correct answer: Option B

v = 2 (v) [L_{2} - L_{1}]

= 2 \times 320 [73 - 20] \times 1 0^{- 2}

= 339.2 m s^{- 1}

\approx

339 m / s

Q4PhysicsNEET UG PYQStanding Waves and Normal Modes

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

n = n_{1} + n_{2} + n_{3}

n = n_{1} + n_{2} + n_{3}

\frac{1}{n} = \frac{1}{n _{1}} + \frac{1}{n _{2}} + \frac{1}{n _{3}}

\frac{1}{n} = \frac{1}{n _{1}} + \frac{1}{n _{2}} + \frac{1}{n _{3}}

Answer key (C) & worked solution

Correct answer: Option C

f \propto \frac{1}{L} \Rightarrow n_{1} : n_{2} : n_{3} = \frac{1}{L _{1}} : \frac{1}{L _{2}} : \frac{1}{L _{3}} L = L_{1} + L_{2} + L_{3} \Rightarrow \frac{1}{n} = \frac{1}{n _{1}} + \frac{1}{n _{2}} + \frac{1}{n _{3}}

Q5PhysicsNEET UG PYQBeats

Three sound waves of equal amplitudes have frequency (n - 1), n, (n + 1). They superimpose to give beats. The number of beats produced per second will be

Answer key (C) & worked solution

Correct answer: Option C

Net beat frequency = LCM of individual beat frequencies = LCM of [(n, n - 1), (n, n + 1), (n - 1, n + 1)] = LCM of (1, 1, 2) = 2 Hz So, no. of beats per second = 2

Q6PhysicsNEET UG PYQStanding Waves and Normal Modes

For sound waves, if the number of nodes for the

5^{th}

harmonic of an open-ended pipe is

n

and that for the

9^{th}

harmonic of the same pipe with one of its ends closed is

m

, the ratio

\frac{n}{m}

\frac{9}{5}

\frac{3}{5}

\frac{5}{9}

Answer key (B) & worked solution

Correct answer: Option B

For open organ pipe → Number of nodes are same as number of harmonics

∴ n = 5

For closed organ pipe → There are only odd harmonics For

1^{st}

harmonic → Number of node → 1 For

3^{rd}

harmonic → Number of node → 2 For

5^{th}

harmonic → Number of node

\to 3

For

7^{th}

harmonic → Number of node

\to 4

For

9^{th}

harmonic → Number of node

\to 5

∴ m = 5

\to \frac{n}{m} = \frac{5}{5} = 1

Q7PhysicsNEET UG PYQDisplacement Relation in a Progressive Wave

A wave travelling in the +ve x-direction having maximum displacement along y-direction as 1 m, wavelength

2 π

m and frequency of

\frac{1}{π} H z

is represented by

Y = s in (x - 2 t)

Y = s in (2 π x - 2 π t)

Y = s in (10 π x - 20 π t)

Y = s in (2 π x - 2 t)

Answer key (A) & worked solution

Correct answer: Option A

The equation of a wave travelling along the x-axis is y=asin(ωt-kx) or y=asin(kx-ωt) Given that

λ = 2 π m; f = \frac{1}{π} H z

∴ k = \frac{2 π}{λ} = \frac{2 π}{2 π} = 1

ω = 2 π f = 2 π \times \frac{1}{π} = 2

a = 1 m (g i v e n am pl i t u d e)

∴ y = s in (x - 2 t)

Q8PhysicsNEET UG PYQStanding Waves and Normal Modes

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

A2 : 1

B1 : 3

C3 : 1

D1 : 2

Answer key (A) & worked solution

Correct answer: Option A

\frac{n _{oop}}{n _{cop}} = \frac{\frac{V}{2 L}}{\frac{V}{4 L}}

\Rightarrow \frac{n _{oop}}{n _{cop}} = \frac{2}{1}

Which topics in Waves carry the most questions?

All 8 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
Standing Waves and Normal Modes	12	110
Speed of a Traveling Wave	5	87
Beats	3	42
Displacement Relation in a Progressive Wave	2	61
Transverse and Longitudinal Waves	0	21
Principle of Superposition of Waves	0	15
Reflection of Waves	0	6
Miscellaneous Examples	0	5

Why does Waves show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in Waves, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test Waves?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the Waves test

Chapters either side of Waves by weight

Mechanical Properties of Fluids Weight 2.9/100 Nuclei Weight 2.9/100 Motion in a Straight Line Weight 2.8/100 Electric Charges and Fields Weight 2.6/100

Waves: NEET PYQs and weightage

Waves: formula sheet for NEET

Wave speed

Wave number and angular frequency

Progressive wave

Transverse wave on a string

Longitudinal wave in a fluid

Longitudinal wave in a solid rod

Speed of sound in a gas (Laplace)

Two equal waves in the same direction

Standing wave

String fixed at both ends

Pipe open at both ends

Pipe closed at one end

Beats

Reflection phase

How does NEET ask Waves?

Which topics in Waves carry the most questions?

Why does Waves show "–" until you answer 3 questions?

What happens when you test Waves?

Chapters either side of Waves by weight