# ICSE Class 10th Physics 3 – Sound MCQs

#### The vibrations of frequency greater than 20,000 Hz are called ____ vibrations.

Correct! Wrong!

The vibrations of frequency greater than 20,000 Hz, which a human ear cannot perceive are known as ultrasonic vibrations.

#### Longitudinal waves can travel in ____.

Correct! Wrong!

Longitudinal wave can travel in solids, liquids and gases.

#### The kind of motion in which transfer of energy takes place when the particles move about their mean position is called ____ motion.

Correct! Wrong!

When a disturbance is created in an elastic medium, it is transferred from one particle to another particle in the form of a wave. This type of propagation is known as wave motion.

#### When the particles of the medium vibrate perpendicular to the propagation of the wave, then the wave is called ____ wave.

Correct! Wrong!

In transverse wave, particles of the medium vibrate perpendicular to the propagation of the wave.

#### A car blowing its horn at 480 Hz moves towards a high wall at a speed of 20 m/s. If the speed of sound is 340 m/s, the frequency of the reflected sound is ____ Hz.

Correct! Wrong!

During reflection, the frequency of sound does not change. Hence, frequency of the reflected sound, n = 480 Hz.

#### A child hears an echo from a cliff 4 seconds after the sound is produced from a cracker. The distance of the cliff from the child is ____ m.

Correct! Wrong!

Consider the distance of the cliff from the child as 'd' Distance = speed of sound × time ⇒ 2d = 344 × 4 ⇒ d = 688 m Hence, the distance of the cliff from the child is 688 m.

#### The time taken by a particle of a medium to complete one vibration is called ____.

Correct! Wrong!

Time taken by a particle of medium to complete one vibration is called time period.

#### The velocity of sound in air is not affected by change in ____.

Correct! Wrong!

Atmospheric pressure does not affect the velocity of sound.

#### A sound wave propagating through a medium has bounced back into the same medium by hitting a hard surface and then such a phenomenon is called ____ of sound.

Correct! Wrong!

A sound wave propagating through a medium has bounced back into the same medium by hitting a hard surface and then such a phenomenon is called reflection of sound.

#### Ultrasonic waves are those waves which a human being can hear.

Correct! Wrong!

Ultrasonic waves are sound waves with a frequency greater than 20 kHz, which is not audible to human being.

#### Which of the following devices, does not work on the principle of multiple reflection of sound?

Correct! Wrong!

Gramophone does not work on the principle of multiple reflection of sound. Devices like megaphone, bulb horn, stethoscope and soundboards work on the principle of multiple reflection of sound.

#### Which of the following frequencies of sound waves are audible to human beings?

Correct! Wrong!

Frequency of 5,000 cycles/second is in the audible range of 20 Hz - 20,000 Hz. Hence, only 5000 cycles/second frequency is audible to human beings.

#### The maximum displacement suffered by the particles of a medium about their mean position is called ____.

Correct! Wrong!

The maximum displacement suffered by the particles of the medium about their mean position is called amplitude.

#### The wave in which the individual particles of a medium oscillate along the direction of wave propagation is called ____.

Correct! Wrong!

The wave in which the individual particles of the medium oscillate along the direction of wave propagation is called longitudinal wave.

#### Which of the following devices, work on the principle of multiple reflection of sound?

Correct! Wrong!

Stethoscope works on the principle of multiple reflection of sound.

#### The voice of ladies is shrill because of ____.

Correct! Wrong!

That property of voice which we call pitch is determined by the rate of vibration of the vocal cords. The greater the number of vibrations per second, the higher the pitch. The rate of vibration, in turn, is determined by the length and thickness of the vocal cords and by the tightening or relaxation of these cords. Normally, women's voices are pitched higher than men's because women's vocal cords are shorter.

#### Among the following properties of a wave, the one that is independent of the other is its ____.

Correct! Wrong!

The maximum displacement of the particle from its mean position is defined as amplitude where the wave is independent of it.

#### The average amount of energy passing through a unit area per unit time in a specified direction is called ____ of the wave.

Correct! Wrong!

Intensity of the wave is defined as the average amount of energy passing through a unit area per unit time in a specified direction.

#### Which of the following is not an example for free vibrations?

Correct! Wrong!

Vibrations of the diaphragm in a radio speaker are according to the frequencies fed to it and are not natural. They are forced vibrations.

#### The speed of sound at 0 °C is 330 m/s. Then, the speed of sound at a temperature of 20 °C is ____ m/s.

Correct! Wrong!

For 1 °C rise in temperature, the increase in speed is 0.6 m/s For 20 °C rise in temperature, the increase in speed is 0.6 × 20 = 12m/s Speed of sound at 20 °C is 330 + 12 Speed of sound at 20 °C is 342 m/s.

#### The frequency of a body executing natural vibrations is called its____ frequency. (i) Natural (ii) damped (iii) forced

Correct! Wrong!

The frequency of a body executing natural vibrations is called its natural frequency.

#### Human ear can perceive sounds ranging from ____.

Correct! Wrong!

Human ear cannot perceive sounds of all frequencies; it can perceive sounds ranging from 20 Hz to 20,000 Hz.

#### The distance between two consecutive crests or troughs is defined as ____.

Correct! Wrong!

The distance between two consecutive crests or troughs is defined as wave length.

#### The characteristic of a sound, which distinguishes a feeble sound from a loud sound of the same frequency is called ____.

Correct! Wrong!

The characteristic of a sound which distinguishes a feeble sound from a loud sound of the same frequency is called loudness.

#### The vibrations of a body that take place under the influence of an external periodic force are called ____ vibrations.

Correct! Wrong!

The vibrations of a body that take place under the influence of an external periodic force are called forced vibrations.

ICSE Class 10th Physics 3 - Sound MCQs
Poor

Average

Good

Excellent