Physics

Wave Motion

489 Questions

Wave motion questions cover the principles of traveling and stationary waves, including their equations and intensities. The topics explore interference patterns, phase differences, and electromagnetic radiation speeds. Mastery of these concepts is vital for physics sections in engineering and civil services examinations.

Wave interferenceStanding wavesPhase differenceElectromagnetic radiationWave equations

Wave Motion Questions

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

How is the frequency of a wave related to its time period?

  1. $\ v=\displaystyle\frac{1}{T}$
  2. $\ T=\displaystyle\frac{1}{v}$
  3. $\ v T=\displaystyle{1}$

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Frequency is the number of occurrences of a repeating event per unit time. The Time period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency.

That is, $T=\dfrac { 1 }{ f } \quad \quad or\quad \quad f=\dfrac { 1 }{ T } $

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

When longitudinal wave propagates through a medium, then the physical quantities propagating in the direction of wave are

  1. Energy

  2. Energy, momentum and mass

  3. Energy and mass

  4. Energy and momentum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When a disturbance is produced in a medium , it is transported by oscillating particles of the medium , the disturbance is a kind of energy and carried by oscillating particles by passing it to the next particle , in this way a longitudinal wave propagates, therefore energy propagates in a longitudinal wave .

As there is no net movement of the medium particles in the propagation of wave , they just vibrate about the centers of rarefaction and compressions , therefore momentum is not transferred in a longitudinal wave . Thus only energy is propagating in the direction of wave. 

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

Choose the Correct answer from alternative given.
The idea of secondary wavelets for the propagation of a wave was first given by:

  1. Newton

  2. Huygens

  3. Maxwell

  4. Fresnel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to the Huygens theory, all the points on a  wavefront act as source for a secondary wavefront or a wavelet which spread outward from the point and move at the speed of light.

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

A transverse wave travelling in a denser medium is reflected from a rarer medium. Then, 

  1. an incident crest is reflected as a crest

  2. an incident crest is reflected as a trough
  3. there is a phase change of $2\pi$ rad
  4. there is a phase change of $\pi/2$ rad
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When a wave reflects from a rarer medium, there is no phase change. Therefore, the crest remains a crest and the trough remains a trough.

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

The wave front due to a source situated at infinity is :

  1. spherical

  2. cylindrical

  3. planar

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • when you considered it a large distance and measuring justice Mall section of it then it can be considered to be plane wavefront source at Infinity 
  • example the one coming from sun to earth surface is considered to be plain VU friend from light diverging from a point source will be spherical
  • So, the wave front due to a source situated at infinity is planar
  • Option  C is the right answer
Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

A : The phase difference between any two points on a wave front is zero
R : From the source light, reaches every point on the wave front in the same time.

  1. Both A and R are true, and R is correct explanation of A

  2. Both A and R are true, and R is not correct explanation of A

  3. A is true but R is false

  4. A is false but R is true
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A wave front is the locus of points having the same phase.
Thus statement A is true because the phase difference is zero as all points have same phase.
Statement R is true because a wavefront is composed of all points where the light reaches from the source in the same time.
As light takes the same time it has the same phase at all points on a wavefront and hence it correctly explains statement A.

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

1: Primary waves can travel in all directions in an ether
2: Secondary waves can travel only in backward in an ether

  1. 1 is true, 2 is false

  2. Both 1 and 2 are true

  3. 1 is false, 2 is true

  4. Both 1 and 2 are false
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Primary wave can travel in all directions in ether.
Secondary waves can travel in forward direction in ether

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

A wave pulse traveling on a two piece string, gets partially reflected and partially transmitted at the junction. The reflected wave is inverted in shape as compared to incident one. If the incident wave has wavelength  $\lambda$  and transmitted wave has  $\lambda ',$  then

  1. $\lambda '> \lambda$
  2. $\lambda' = \lambda$
  3. $\lambda' < \lambda$

  4. none
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reflected wave is inverted hence second medium is dir sec with respect to first medium. $\lambda ' < \lambda $

$\frac{{\lambda '}}{t} < \frac{\lambda }{t} \Rightarrow \lambda ' < \lambda $
Ans. (C)

Multiple choice physics wave optics huygens wave theory and wavefront wave propagation (huygens' construction) theories on light wave behaviour

The wave front due to a point source at a finite distance from the source is -

  1. Spherical

  2. Cylindrical

  3. Plane

  4. Circular
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A wavefront originating from a localized point source spreads out uniformly in all directions in three-dimensional space, forming expanding concentric spheres at finite distances.

Multiple choice physics study of sound reverberation applications of reflection of sound multiple reflection of sound and reverberation applications of ultrasound

(1) The reflected pulse will be in same orientation of incident pulse due to a phase change of $\pi$ radians.
(2) During reflection the wall exerts a force on string in upward direction.
For the above given two statements choose the correct option given below.

  1. Only (1) is true

  2. Only (2) is true

  3. Both are true

  4. Both are wrong
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The pulse will be of same orientation as before after the phase change of $2\pi$ radians

During the reflection string tries to move upward but wall applies downward force to stop movement of connected end. So both the statements are wrong.