Tag: physics

Questions Related to physics

The wave produced by a motor boat sailing in water are

  1. Transverse

  2. Longitudinal

  3. Longitudinal and Transverse

  4. Stationary


Correct Option: C
Explanation:

The waves produced by a motorboat sailing in water are of both transverse and longitudinal type. Transverse waves are produced on the surface and longitudinal waves are produced deep inside the water.

A crest is the point of maximum displacement of a particle in a wave. State whether true or false.

  1. True

  2. False


Correct Option: A
Explanation:

A crest is a point on the wave with the maximum value of upward displacement within a cycle. A crest is a point on the surface wave where the displacement of the medium is the maximum.

Transverse mechanical wave can travel in

  1. Iron rod

  2. Hydrogen gas

  3. Water surface

  4. Stretched string


Correct Option: A,C,D
Explanation:

Transverse waves can travel only in solids and only along the surface of liquids, but not in the entire liquid. They can't travel in gases.

Since iron rod and stretched string are solids, transverse waves can travel in them.
Water surface being a liquid surface they can travel in it also.
Hydrogen gas being a gas, they can't travel in it.

Which of the following can travel through vacuum?

  1. Light waves

  2. Heat waves

  3. $X$-rays

  4. Sound waves


Correct Option: A,B,C
Explanation:

Heat rays are infra-red rays.

Light rays, infra-red rays and X-rays are all electromagnetic rays.
Electromagnetic rays can travel through vacuum and through transperent media.
However, sound waves are mechanical longitudinal waves. They need a material medium for travelling. They can't travel through vacuum.

Which of the following does not identify a necessary property of wave motion?

  1. transmission of energy

  2. periodic motion

  3. disturbance

  4. a material medium


Correct Option: D
Explanation:

In any wave motion, energy is always transferred to the next particle which is succeeding the previous particle.  In a wave motion, particles are oscillating in a direction perpendicular to the direction of propagation or parallel. Since oscillation is a periodic motion,  we can say that periodic motion is always associated with the wave.  An oscillatory disturbance is always imparted the next and next particle and this is how the disturbance Travels across the particles.  Ordinary waves require a material medium for propagation. But electromagnetic waves do not require any material medium. They can also propagate through vacuum. Thus material medium is not a necessary condition for all wave motions.

During propagation of a plane progressive mechanical wave :

  1. all the particles are vibrating in the same phase

  2. amplitude of all the particles is equal

  3. particles of the medium execute S.H.M.

  4. wave velocity depends upon the nature of the medium


Correct Option: B,C,D
Explanation:

During propagation of a plane progressive mechanical wave amplitude of all the particles is equal, particle of the medium execute S.H.M, wave velocity depends upon the nature of the medium and all the particles are vibrating in the different phase.

Hence $B, C$ and $D$ are correct options.

Distance between crest and through is

  1. $\displaystyle \frac{\lambda}{4}$

  2. $\displaystyle \frac{2\lambda}{6}$

  3. $\displaystyle \frac{\lambda}{2}$

  4. $\displaystyle \frac{2\lambda}{3}$


Correct Option: C

A point on the wave, wherein the displacement of the wave is ___________ is known as a crest

  1. Maximum

  2. Minimum

  3. Zero

  4. None of the above


Correct Option: A
Explanation:

crest is a point on the wave where the displacement of the medium is at a maximum

The correct option is (a)

A string tied to a wall is given a flip at the other end with an initial velocity u, which generates a curve. After sometime, this curve is seen to reach the wall with the same speed. The transfer of the kinetic energy takes place due to

  1. air molecules surrounding the string

  2. sound wave carried by the string

  3. molecules on the string

  4. none of the above


Correct Option: C
Explanation:

For the wave to propogate, it needs a mechanical medium and this uses the molecules of string to propogate the energy


The correct option is (c)

A heat energy of 540 kJ ,given to 1 litre of water at 100C makes the water to boil. In this process, heat energy is transferred from the source to water by means of 

  1. water

  2. steam

  3. air

  4. none of the above


Correct Option: A
Explanation:

Water acts as a medium to transfer heat energy from the source

The correct option is (a)