Waves MCQs
Which of a following is a primary characteristic of a mechanical wave?
It can travel through a vacuum.
It transports energy and matter.
It requires a medium.
Its speed is constant in all media.
In a transverse wave, the particles of the medium oscillate in which direction relative to the wave's direction of propagation?
Parallel to propagation.
Perpendicular to propagation.
In a circular motion.
They do not oscillate.
The distance between two consecutive crests or troughs of a wave is known as the:
Amplitude
Frequency
Period
Wavelength
The relationship between wave speed (v), frequency (f), and wavelength (λ) is given by:
v = f / λ
v = λ / f
v = f × λ
f = v × λ
Newton's formula for the speed of sound in a gas assumed the process of compressions and rarefactions was:
Isothermal
Adiabatic
Isobaric
Isochoric
Laplace corrected Newton's formula by suggesting the process is adiabatic. This correction involves multiplying the pressure by a factor of:
The speed of sound in a gas is independent of:
Temperature
Density
Pressure
None
When two waves meet at a point in a medium simultaneously, the resultant displacement is the vector sum of the individual displacements. This is known as the:
Huygens' Principle
Doppler Effect
Principle of Superposition
Principle of Interference
Constructive interference occurs when two waves meet in phase, meaning their path difference is:
(n + 1/2)λ
nλ
Odd multiple of λ/4
Zero only
The phenomenon of beats is produced by the superposition of two waves of slightly different:
Amplitudes
Speeds
Frequencies
Wavelengths
If two tuning forks of frequencies 256 Hz and 260 Hz are sounded together, the number of beats heard per second is:
When a wave is reflected from a denser medium, what is the phase change it undergoes?
0 degrees
90 degrees
180 degrees
270 degrees
Stationary waves are formed by the superposition of two identical waves traveling:
In same direction, phase diff π.
In opposite directions.
In same direction, same phase.
Perpendicular to each other.
In a stationary wave, the points of zero amplitude are called:
Antinodes
Crests
Troughs
Nodes
The distance between two consecutive nodes in a stationary wave is:
For a stretched string of length L fixed at both ends, the wavelength of the fundamental mode of vibration (first harmonic) is:
For an air column in a pipe closed at one end, which of the following is true for the resonant modes?
All harmonics are present.
Only even harmonics are present.
Only odd harmonics are present.
No harmonics are present.
The Doppler effect is the apparent change in a wave's ________ due to relative motion between the source and the observer.
Speed
Amplitude
Frequency
Phase
When a sound source moves towards a stationary observer, the apparent frequency heard by the observer:
Increases
Decreases
Remains the same
Becomes zero
Which of the following is an application of the Doppler effect?
Tuning a musical instrument.
Radar gun for speed measurement.
Using sunglasses to reduce glare.
Creating an echo.
The compressions and rarefactions in a longitudinal wave are analogous to what features of a transverse wave?
Amplitude and wavelength
Nodes and antinodes
Crests and troughs
Frequency and period
What happens to the wavelength of a wave when it passes from a denser to a rarer medium?
It decreases.
It increases.
It remains unchanged.
It becomes zero.
The energy of a wave is directly proportional to the square of its:
Wavelength
Frequency
Speed
Amplitude
In an open organ pipe (open at both ends), the fundamental frequency corresponds to a standing wave with:
Nodes at both ends.
Antinodes at both ends.
Node at one end, antinode at other.
Two nodes, three antinodes.
For a given temperature, the speed of sound is greatest in which state of matter?
The effect of humidity on the speed of sound in air is that the speed:
Increases
Decreases
Remains unchanged
Becomes zero
Two waves are said to be coherent if they have:
Same amplitude and frequency.
Same frequency, constant phase difference.
Same speed and amplitude.
Same wavelength and are in phase.
The loudness of a sound is most closely related to its:
Frequency
Wavelength
Speed
Amplitude
Which phenomenon demonstrates that light waves are transverse?
Interference
Diffraction
Reflection
Polarization
If the tension in a stretched string is quadrupled, its fundamental frequency of vibration becomes:
Half
Doubled
Quadrupled
Unchanged
A wave pulse is a disturbance that is:
Continuous and periodic.
Of short duration.
Always transverse.
Stationary.
The time period of a simple pendulum is T. If its length is quadrupled, the new time period will be:
A 'shock wave' or 'sonic boom' is produced when an object travels:
Slower than sound.
At the speed of sound.
Faster than sound.
In a high-speed circular path.
The quality or timbre of a musical sound depends on:
Fundamental frequency only.
Amplitude of the wave.
Harmonics and their intensities.
Speed of sound.
The bending of waves as they pass through a narrow opening or around an obstacle is called:
Reflection
Refraction
Interference
Diffraction
Two points on a wave are in the same phase if the distance between them is:
The speed of a transverse wave on a stretched string is given by v = √(T/μ). The term μ represents:
Mass of the string.
Length of the string.
Linear mass density.
Tension in the string.
If the length of a pipe closed at one end is 0.25 m, what is the wavelength of its fundamental resonant frequency?
An observer is moving away from a stationary source of sound. The apparent pitch heard by the observer will be:
Higher than actual pitch.
Lower than actual pitch.
Same as actual pitch.
Fluctuating.
Which of the following does NOT change when a wave enters a new medium?
Speed
Frequency
Wavelength
Direction
The intensity of a wave from a point source decreases with distance (r) from the source according to which relationship?
I ∝ 1/r
I ∝ 1/r²
I ∝ r
I ∝ r²
A string vibrates in 5 segments (loops). This corresponds to which harmonic?
3rd harmonic
4th harmonic
5th harmonic
10th harmonic
What is the phase difference between particles at a node and an adjacent antinode in a stationary wave?
0 degrees
90 degrees
180 degrees
360 degrees
The phenomenon of 'resonance' occurs when the frequency of an applied force is:
Much higher than natural frequency.
Much lower than natural frequency.
Equal to natural frequency.
Half the natural frequency.
A sound wave has a frequency of 500 Hz and a speed of 340 m/s. What is its wavelength?
1.47 m
170000 m
0.68 m
0.50 m
If a wave reflects from a 'free end' or a less dense medium, the reflected wave has a phase change of:
0 degrees
90 degrees
180 degrees
270 degrees
In the equation for a progressive wave, y = A sin(kx - ωt), the term 'k' is known as the:
Amplitude
Angular frequency
Wave number
Phase constant
The energy in a stationary wave is:
Transported continuously.
Zero everywhere.
Maximum at the nodes.
Confined between nodes.
A siren (1000 Hz) moves away from an observer towards a cliff at 10 m/s. What is the frequency of the echo heard? (v_sound = 330 m/s)
970 Hz
1000 Hz
1031 Hz
1062 Hz
The second overtone of a closed organ pipe is equivalent to which harmonic?
3rd harmonic
4th harmonic
5th harmonic
6th harmonic
The maximum velocity of a particle in a simple harmonic wave (v_max = ωA) occurs when the particle is at:
The extreme position.
The equilibrium position.
Midway between mean and extreme.
Any point (velocity is constant).
How does the speed of sound in air change if the absolute temperature is quadrupled?
Becomes four times faster.
Becomes half as fast.
Becomes twice as fast.
Remains unchanged.
Two sound waves have frequencies of 400 Hz and 405 Hz. What is the time interval between successive beats?
An open organ pipe is 0.5 m long. What is the frequency of its third harmonic? (v_sound = 340 m/s)
340 Hz
680 Hz
1020 Hz
510 Hz
What is the phase difference between two points on a progressive wave separated by a distance of λ/4?
π radians
2π radians
π/2 radians
π/4 radians
Red shift in the light from distant galaxies is an example of:
Interference
Polarization
The Doppler effect
Diffraction
When a longitudinal wave travels through a medium, what is transported?
Energy only
Matter only
Energy and matter
Neither energy nor matter
The second overtone of a vibrating string fixed at both ends corresponds to which harmonic?
2nd harmonic
3rd harmonic
4th harmonic
1st harmonic
In a displacement-position graph of a wave, the amplitude is represented by the:
Horizontal distance between crests.
Slope of the graph.
Maximum vertical displacement.
Area under one cycle.
In a resonance tube, if the first resonance is at length L₁ and the second is at L₂, the wavelength is:
L₂ - L₁
2(L₂ - L₁)
(L₂ - L₁)/2
L₁ + L₂
In the equation y = A sin(kx - ωt), the term ω represents the:
Wave number
Wave speed
Angular frequency
Wavelength
If the density of a gas is quadrupled at constant pressure, the speed of sound will:
Be doubled
Be halved
Become four times
Remain unchanged
Destructive interference will be complete if the two interfering waves have:
Same freq, amplitude, and π phase difference.
Same freq, different amplitudes, π phase difference.
Different freqs, same amplitude, in phase.
Same freq, amplitude, and in phase.
All particles in a stationary wave between two consecutive nodes vibrate:
With same frequency and amplitude.
With same frequency, different amplitudes.
With different frequencies and amplitudes.
In opposite phase, different amplitudes.
The speed of light in a vacuum is 3×10⁸ m/s. What is its speed in a medium with a refractive index of 1.5?
Remains the same.
Increases.
Becomes 2×10⁸ m/s.
Becomes 4.5×10⁸ m/s.
A string of length L has frequency f. If length is halved and tension is doubled, the new frequency will be:
The 'pitch' of a musical note is determined by its:
Amplitude
Frequency
Waveform
Speed
A car (20 m/s, horn 500 Hz) chases a cyclist (10 m/s). What is the frequency heard by the cyclist? (v_sound = 340 m/s)
500 Hz
515.6 Hz
484.4 Hz
531.3 Hz
Which of these is NOT a mechanical wave?
Sound waves
Water waves
Waves on a string
Radio waves
The SI unit of wave number (k) is:
At the crest of a transverse wave, the instantaneous acceleration of a particle is:
Zero.
Maximal and upward.
Maximal and downward.
Constant.
The wave velocity (v) is related to the maximum particle velocity (v_max) by:
v = v_max
v = (k/ω)v_max
No general relation.
No simple relation.
Huygens' principle can be used to explain:
Particle nature of light.
Photoelectric effect.
Reflection, refraction, and diffraction.
Quantization of energy.
A wave is described by y(x,t) = 0.05 sin(2πx - 4πt). What is its speed?
Ultrasound has a frequency that is:
Below 20 Hz
Between 20 Hz and 20 kHz
Above 20 kHz
Exactly 20 kHz
When temperature increases, the frequency of a tuning fork:
Increases
Decreases
Remains the same
Becomes zero
In stationary waves, the net transfer of energy is:
Maximum
Constant but not zero
Zero
Dependent on amplitude
A sonometer wire of length L vibrates in its fundamental mode. The standing wave has:
One node, one antinode.
Two nodes, one antinode.
One node, two antinodes.
Two nodes, two antinodes.
Which of the following properties of a wave is independent of the others?
Speed
Wavelength
Frequency
Amplitude
Earthquake waves are an example of:
Transverse waves only
Longitudinal waves only
Both transverse and longitudinal
Electromagnetic waves
A bat emits ultrasound (50 kHz) and hears an echo after 0.1 s. How far away is the insect? (v_sound = 340 m/s)
Two waves of equal amplitude and frequency interfere. The resultant amplitude is maximum when the phase difference is:
π/2
π
3π/2
2nπ (n is integer)
A wave pulse on a string moves from a less dense to a more dense section. The pulse will be:
Only transmitted.
Only reflected and inverted.
Partly transmitted, partly reflected & inverted.
Partly transmitted, partly reflected, not inverted.
The effect of loading a tuning fork with wax is to:
Increase its frequency.
Decrease its frequency.
Increase amplitude.
Decrease amplitude.
A train approaches a station platform at 20 m/s, blowing a 200 Hz whistle. What is the wavelength heard by a person on the platform? (v_sound = 340 m/s)
Sound waves cannot be polarized because they:
Are transverse waves.
Are longitudinal waves.
Have a very high speed.
Have a very long wavelength.
Silence zones are created in an auditorium due to:
Constructive interference
Beats
Destructive interference
Resonance
A simple pendulum has a time period T on Earth. If it is taken to the Moon (gravity is 1/6th of Earth's), its new time period will be:
Which statement is true for both longitudinal and transverse waves?
They can be polarized.
They travel as compressions.
They transfer energy.
Particles vibrate parallel to wave propagation.
The intensity of a sound wave is proportional to the square of:
Wavelength
Wave speed
Time period
Amplitude
A closed organ pipe and an open organ pipe of the same length are sounded. The ratio of their fundamental frequencies is:
The phenomenon where a vibrating body causes another body to vibrate with the same frequency is called:
Beats
Resonance
Forced vibration
Damped oscillation
Two cars move in opposite directions at the same speed. If one blows a horn, the pitch heard by the other driver will be:
Highest when approaching.
Highest when moving away.
Highest when just crossing.
Same as the original pitch.
The distance between a node and the next antinode in a stationary wave is:
The spreading of a wave passing through an aperture is more pronounced when the:
Wavelength is smaller than aperture.
Wavelength is comparable to aperture.
Frequency is very high.
Amplitude is large.
If the tension of a string is increased by 21%, the percentage increase in its fundamental frequency will be approximately:
A progressive wave is represented by y = 5 sin(100πt - 2πx). What is the wavelength of the wave?
Which of the following is an essential condition for producing beats?
The sources have the same frequency.
The sources have slightly different frequencies.
The sources have the same amplitude.
The sources are moving.
Water waves are an example of:
Transverse waves only
Longitudinal waves only
Both transverse and longitudinal waves
Stationary waves
Other Physics Topics MCQs
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