Question 1

The force which tries to bring the body back to its mean position is called
A)deforming force
B)restoring force
C)gravitational force
D)buoyant force

Accepted Answer

Restoring force is the force that acts to bring a body back to its equilibrium or mean position when it is displaced. This force acts in the opposite direction to the displacement.

Question 2

In which of the following media will sound travel the fastest?
A)solid
B)both solid and liquid
C)liquid
D)gas

Accepted Answer

Sound travels fastest in solids because particles in a solid medium are much closer together than in liquids or gases, allowing sound waves to be transmitted more quickly.

Question 3

Sound waves in air are _____ waves.
A)longitudinal
B)radio
C)transverse
D)electromagnetic

Accepted Answer

Sound waves in air are longitudinal waves, meaning the oscillation of the medium (air, in this case) is parallel to the direction of the wave propagation.

Question 4

Sound waves cannot pass through
A)a solid-liquid mixture
B)an ideal gas
C)a liquid-gas mixture
D)a perfect vacuum

Accepted Answer

Sound waves require a medium to travel through because they are mechanical waves, which means they propagate through the vibration of particles in a medium. A perfect vacuum does not contain any particles to vibrate, thus sound cannot propagate through it.

Question 5

Out of the following, which frequency is not clearly audible to the human ear?
A)30 Hz
B)30,000 Hz
C)300 Hz
D)3000 Hz

Accepted Answer

The average human ear can hear frequencies between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz, like 30,000 Hz, are not clearly audible to the human ear.

Question 6

The distance between two consecutive crests is L, then the wavelength is given by
A)L/2
B)2 L
C)4 L
D)L

Accepted Answer

The distance between two consecutive crests of a wave is one wavelength, hence the wavelength is L.

Question 7

The frequency of a wave is 5 Hz. It refers to (type of wave)
A)ultrasonics
B)microwaves
C)infrasonics
D)radio waves

Accepted Answer

Infrasonics refers to sound waves that are below the frequency of 20 Hz, which is below the lower limit of human hearing. Since 5 Hz is below this threshold, it is considered infrasonic.

Question 8

A pulse is a wave
A)of high duration
B)of short duration
C)which travels in vacuum only
D)which travels in solids only

Accepted Answer

A pulse is a wave of short duration, characterized by a single disturbance that travels through a medium or space, unlike continuous waves which extend over a longer period. Pulses can travel through various mediums, not just in vacuum or solids, making options C and D incorrect. Option A is also incorrect because pulses are defined by their short, rather than long, duration.

Question 9

Which of the following types of waves is different from others?
A)Light waves
B)X-rays
C)Radio waves
D)Sound waves

Accepted Answer

Sound waves are mechanical waves that require a medium to travel through, unlike light waves, X-rays, and radio waves, which are electromagnetic waves and can travel through a vacuum.

Question 10

Waves produced by supersonic jet planes are
A)shock waves
B)seismic waves
C)infrasonics
D)none of these

Accepted Answer

Shock waves are produced by supersonic jet planes when they travel faster than the speed of sound, creating a sudden change in pressure.

Question 11

Echo is produced due to
A)reflection of sound
B)refraction of sound
C)resonance
D)none of these

Accepted Answer

Echo is produced due to the reflection of sound waves when they bounce back after hitting a hard surface or obstacle. This phenomenon allows the sound to be heard again or echoed.

Question 12

SONAR is based on the principle of
A)echo
B)resonance
C)reverberation
D)any one of the above

Accepted Answer

SONAR (Sound Navigation and Ranging) is based on the principle of echo, where sound waves are emitted and their reflections from objects are used to determine the location or distance of those objects under water.

Question 13

Which of the following frequencies of sound cannot be heard by human beings?
A)5 Hz
B)20 Hz
C)400 Hz
D)1000 Hz

Accepted Answer

The average human ear can hear sounds between 20 Hz and 20,000 Hz. Sounds below 20 Hz are considered infrasound and cannot be heard by humans, making 5 Hz inaudible.

Question 14

The mirror used in automobiles to see the rear field of view is
A)concave
B)convex
C)plane
D)none of these

Accepted Answer

Convex mirrors are used in automobiles because they provide a wider field of view, allowing drivers to see more of the area behind them. This helps in reducing blind spots and enhances safety while driving.

Question 15

The mirror used in search lights is
A)concave
B)convex
C)plane
D)none of these

Accepted Answer

Concave mirrors are used in search lights because they can focus light into a parallel beam, which is ideal for directing light over long distances.

Question 16

Shaving mirrors are
A)convex mirrors
B)concave mirrors
C)plane mirrors
D)none of these

Accepted Answer

Shaving mirrors are concave mirrors because they produce an enlarged and upright image of the face, making it easier to see details for shaving or applying makeup. Concave mirrors converge light, allowing for a closer and more detailed view.

Question 17

The laws of reflection are true for
A)the plane mirror only
B)the concave mirror only
C)the convex mirror only
D)all reflecting surfaces

Accepted Answer

The laws of reflection apply universally to all reflecting surfaces, including plane mirrors, concave mirrors, and convex mirrors, not just a specific type. These laws state that the angle of incidence equals the angle of reflection, and they apply regardless of the shape of the reflecting surface.

Question 18

When the object is at focus of a concave mirror, the image is formed at
A)focus
B)centre of curvature
C)within focus
D)infinity

Accepted Answer

When an object is placed at the focus of a concave mirror, the reflected rays are parallel and the image is formed at infinity.

Question 19

Which of the following is a non-luminous body?
A)fire
B)sun
C)stars
D)earth

Accepted Answer

Non-luminous bodies do not produce their own light but can reflect light from other sources. The Earth is a non-luminous body because it reflects light from the Sun, unlike fire, the Sun, and stars, which generate their own light.

Question 20

A body which allows most of the light to pass through it is called a
A)transparent body
B)opaque body
C)translucent body
D)none of these

Accepted Answer

Transparent bodies allow most of the light to pass through them, enabling us to see clearly through them.

Quiz 9: Waves and Light

The force which tries to bring the body back to its mean position is called

In which of the following media will sound travel the fastest?

Sound waves in air are _____ waves.

Sound waves cannot pass through

Out of the following, which frequency is not clearly audible to the human ear?

The distance between two consecutive crests is L, then the wavelength is given by

The frequency of a wave is 5 Hz. It refers to (type of wave)

A pulse is a wave

Which of the following types of waves is different from others?

Waves produced by supersonic jet planes are

Echo is produced due to

SONAR is based on the principle of

Which of the following frequencies of sound cannot be heard by human beings?

The mirror used in automobiles to see the rear field of view is

The mirror used in search lights is

Shaving mirrors are

The laws of reflection are true for

When the object is at focus of a concave mirror, the image is formed at

Which of the following is a non-luminous body?

A body which allows most of the light to pass through it is called a