(English Medium) ICSE Class 10 - CISCE Important Questions for Physics

State one important property of waves used for echo depth sounding.

Displacement distance graph of two sound waves A and B, travelling in a medium, are as shown in the diagram below.

Study the two sound waves and compare their:

1) Amplitudes

2) Wavelengths

What do you understand by free vibrations of a body?

Why does the amplitude of a vibrating body continuously decrease during damped vibrations?

The diagram above shows a wire stretched over a sonometer. Stems of two vibrating tuning forks A and Bare touched to the wooden box of the sonometer. It is observed that the paper rider (a small piece of paper folded at the centre) present on the wire flies off when the stem of vibrating tuning fork B is touched to the wooden box but the paper just vibrates when the stem of vibrating tuning fork A is touched to the wooden box.

1) Name the phenomenon when the paper rider just vibrates.

2) Name the phenomenon when the paper rider flies off.

3) Why does the paper rider fly off when the stem of tuning fork B is touched to the box?

A person is standing at the seashore. An observer on the ship which is anchored in between a vertical cliff and the person on the shore fires a gun. The person on the shore hears two sounds, 2 seconds and 3 seconds after seeing the smoke of the fired gun. If the speed of sound in the air is 320 ms-1 then calculate:

1) the distance between the observer on the ship and the person on the shore.

2) the distance between the cliff and the observer on the ship.

When a body vibrates under a periodic force, the vibrations of the body are ______.

A man playing a flute is able to produce notes of different frequencies. If he closes the holes near his mouth, will the pitch of the note produced, increase or decrease? Give a reason.

Two waves of the same pitch have amplitudes in the ratio 1 : 3. What will be the ratio of their : 
(i) intensities and
(ii) frequencies

(i) Define resonant vibrations. 
(ii) Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him?

It is observed that during march-past we hear a base drum distinctly from a distance compared to the side drums.
(i) Name the characteristics of sound associated with the above obervation.
(ii) Give a reason for the above observation.

Two pendulums C and D are suspended from a wire as shown in the figure give below. Pendulum C is made  to oscullate by displaying it from its mean position. It is seen that D also starts oscillating. 

(i) Name the type of oscillation, C will execute.
(ii) Name the type of oscillation, D will execute.
(iii) If the length of D is made equal to C then what difference will you notice in the oscillations of D ?
(iv) What is the name of the phenomenon when the length of D is made equal to C ?

Pendulums A, B, C and D are tied to a flexible string PQ and are at rest. Pendulum C is disturbed. Which of the following statements is true?

Resonance is ______.

(a) Which one of the following graphs A or B shows free vibrations in a vacuum and which one shows free vibrations in a medium?

(b) How did you come to this conclusion.

1. Define pitch.
2. Two wires AB and CD of same length are stretched by same amount. Which wire will produce a sound of greater pitch on plucking?
3. Give a reason for your answer.

A change in amplitude of a sound wave is noticed.

1. Which characteristic of sound is affected due to the above change?
2. How is amplitude related to your answer to part (a) above?
3. What happens to the quality of the sound?

Two notes are produced from two different musical instruments, such that they have same loudness and same pitch. The produced notes differ in their ______.

A metal foot ruler is held at the edge of a table. It is pressed at its free end and then released. It vibrates.

1. Name the vibrations produced.
2. State one way to increase the frequency of these vibrations.