(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

What is the effect of temperature and pressure on the speed of sound in a gas?

What is sound? Explain with example how does sound travel in a medium.

The smoke from the gun barrel is seen 2 second before the explosion is heard. If the speed of sound in air is 350 ms^-1, calculate the distance of observer from the gun.

The sound of which of the following frequency is audible to us?
2 Hz, 1000 Hz, 200 kHz, 8 MHz

The angle between an incident ray and the mirror is 35⁰.
(i) What is the angle of incidence?
(ii) What is the angle of reflection?
(iii) What is the total angle turned by the ray of light?
(iv) What is the angle between the incident and the reflected rays?

A boy is standing in front of a plane mirror at a distance of 3 m from it.
(i) What is the distance between the boy and his image?
(ii) If the boy moves 1 m backward, find the distance between the image and the boy.

The reflection of a ray of light (OA) normally incident on a plane mirror is shown below

What are the angles of incidence and reflection?

Distinguish between light and sound waves. What are the consequences of the large difference in the speed of sound and that of light? Briefly explain them.

Show an incident ray AO and the normal ON a plan mirror. draw the reflected ray and then find the angle between the incident and reflected rays.

Draw two sets of rays of light to show the formation of an image of the letter as shown in figure p.

State whether the following statement is true or false. If false, correct it.

The angle of incidence is the angle made by the incident ray with the plane mirror.