Physics

Wave Motion

536 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 study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

Match the columns

i) particles of medium move parallel to the propagation of disturbance. a) Transverse wars
ii) particles of medium oscillate up and down about their mean position. b) longitudual wars.
iii) particles of the medium oscillate oscillate back and forth about their position of vest.
iv) particles move about their mean positions in a direction perpendicular to the direction of waves propagation

  1. a - i, ii, b - iii, iv

  2. a - i, iii, b - ii, iv

  3. a - iii, iv, b - i, ii

  4. a - iv, ii, b - i, iii
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a wave if the particles of medium , vibrate perpendicular to the direction of wave motion (disturbance) then this wave is called a longitudinal wave .

 If the particles of medium , vibrate parallel to the direction of wave motion (disturbance) then this wave is called a transverse wave .
According to these definitions , we can match the given columns as :
a-iv ,ii and b-i,iii . 

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as:

  1. transverse wave

  2. propagated waves

  3. longitudinal waves

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

The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as transverse wave. Examples of these waves are: vibrations in strings, ripples on water surface and electromagnetic waves.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

How longitudinal waves are different from other waves?

  1. Particles of medium move in a direction parallel to direction of energy transport

  2. Particles of medium move in a direction perpendicular to direction of energy transport

  3. Particles of medium move in a direction below to direction of energy transport

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Longitudinal waves are different from the others waves because in longitudinal waves particles of medium move in a direction parallel to direction of energy transport for longitudinal waves.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

In a graphical presentation of longitudinal waves as attached, the peak of wave is called

  1. Compression

  2. Rarefaction

  3. Reflection

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

Graphical representation of longitudinal waves is the variation of pressure (y-axis) with the distance (x-axis). We know that, the pressure is higher at the point where the element of medium is compressed and the pressure is low where the element of medium is rarefied.
So, the wave forms a pressure peak at compression and pressure valley at rarefaction.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

In the graphical presentation as attached, what does the valley of wave known as

  1. Compression

  2. Rarefaction

  3. Reflection

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

Graphical representation of longitudinal waves is the variation of pressure (y-axis) with the distance (x-axis). We know that, the pressure is higher at the point where the element of medium is compressed and the pressure is low where the element of medium is rarefied.
So, the wave forms a pressure peak at compression and pressure valley at rarefaction.

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

A longitudinal waves consists of

  1. crest and troughs in the medium

  2. compressions and rarefactions in the medium

  3. crest and troughs in vacuum

  4. Both A and B
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave. Longitudinal waves are also called compression waves or compression waves, because they produce compression and rarefaction when traveling through a medium.  In longitudinal waves, the displacement of the particle's is parallel to the propagation of the wave. 

Multiple choice physics study of sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

In case of longitudinal waves, the particles of medium vibrate

  1. in the direction of wave propagation

  2. opposite to the direction of wave propagation

  3. at right angles to the direction of wave propagation

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as the direction of travel of the wave. Longitudinal waves are also called compressional waves or compression waves, because they produce compression and rarefaction when traveling through a medium.

Multiple choice physics sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

769Hz longitudinal wave in air has a speed of 344m/s. How much time is required for the phase to change by 90 degrees at a given point in space? 

  1. 0.325 ms

  2. 3.25 ms

  3. 32.5 ms

  4. 325 ms
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given that, 

The frequency of wave is $\nu = 769 Hz$.

The speed of wave is $v = 344 ms^{-1}$.

We know, the frequency of a wave is the number of oscillations per 
unit time. The period (T) of a wave is the time that it takes for one complete oscillation, i.e., to change its phase through $360^\circ$.
Hence,

$T = \dfrac{1}{\nu}$

$T = \dfrac{1}{769}$

$T = 0.0013 s$

$T = 1.3 ms$
Here, the phase change is 90 degrees at a given point in space.  

$\dfrac{90}{360} = \dfrac{1}{4}$

Hence, the time period required to complete one fourth oscillation is

$T = \dfrac{1.3}{4} = 0.325 ms$

Multiple choice physics sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

The type of waves that can be propagated in solids are :

  1. Longitudinal

  2. Transverse

  3. both

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

Mechanical waves (longitudinal waves and transverse waves) are waves which propagate through a material medium (solid, liquid or gas) at a wave speed which depends on the elastic and inertial properties of that medium. 
The transverse waves depends on the rigidity of the medium hence, can propagate through solid and liquid medium but not through gases.
The longitudinal waves depends on resistance to compression or volume elasticity of the medium hence, can propagate through solid, liquid and gases.

Multiple choice physics sound sound as a wave of disturbance vibrations in a tuning fork vibrations in tuning fork

When slinky is stretched out in a horizontal direction and first coils are vibrated horizontally then which waves are generated?

  1. Longitudinal Waves

  2. Transverse Waves

  3. Surface waves

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Longitudinal Waves are generated when slinky is stretched out in a horizontal direction and first coils are vibrated horizontally 

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

Wave front means:

  1. all particles in it have same phase

  2. few particles are in same phase, rest are in opposite phase

  3. all particles have opposite phase of vibrations

  4. all particles have random vibrations
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All particles in it have same phase.

It is the imaginary surface representing corresponding points pf a wave that vibrate in unison. When identical waves having a common origin travel through a homogeneous medium , the corresponding crests and troughs at any instant phase.

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

A wavefront is an imaginary surface where :

  1. phase is same for all points

  2. phase changes at constant rate at all points along the surface

  3. constant phase difference continuously changes between the points

  4. phase changes all over the surface
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A wave front is the locus of points having the same phase.
Hence option A is correct.

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

The wavefront is a surface in which

  1. all points are in the same phase

  2. there is a pair of points in opposite phase
  3. there is a pair of points with phase difference $(\dfrac{\pi}{2})$

  4. there is no relation between the phases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A wavefront is the locus of points characterized by propagation of position of the same phase: a propagation of a line in 1D, a curve in 2D or a surface for a wave in 3D.