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

Name the material used for making the armature of an electric bell. Give a reason for your answer. 

Atmospheric pressure at sea level is 76 cm of mercury. Calculate the vertical height of the air column exerting the above pressure. Assume the density of air 1.29 kgm⁻³ and that of mercury is 13600 kgm⁻³. Why the height calculated by you is far less than the actual height of the atmosphere?

The radius of the press plunger and pump plunger are in ratio of 50 : 4. If an effort of 20 kgf acts on the pump plunger, calculate the maximum effort which the press plunger can over come.

Select the correct option.

As we move upwards, the atmospheric pressure

Select the correct option.

The atmospheric pressure on the earth’s surface is approximately

By drawing a neat diagram define the following:

Mirror

Explain the following term:

Normal Draw

diagram/diagrams to show them.

A ray of light strikes a plane mirror, such that the angle with the mirror is 20°. What is the value of angle of reflection? What is the angle between the incident ray and the reflected ray?

Prove experimentally that images are formed as far behind in a plane mirror as the object is in front of it.

Prove geometrically that when plane mirror turns through a certain angle, the reflected ray turns through twice the angle.

(a) What do you understand by the term lateral inversion?
(b) A printed card has letters PHYSICS. By drawing the diagram show the appearance of the letters. (No ray diagram is required).

State the mirror formula for the formation of total number of images formed in two plane mirrors, held at an angle.

Calculate the number of images formed in two plane mirrors, when they are held at the angle of (i) 72° (ii) 36°.

Draw a neat two ray diagram for the formation of images in two plane mirrors, when mirrors are at right angles to each other.

Draw a neat two ray diagram for the formation of images in two plane mirrors, when mirrors are at facing each other.

What should be the minimum size of a plane mirror, so that a person 182 cm high can see himself completely?

A boy stands 4 m away from the plane mirror. If the boy moves `1/2` m towards the mirror, what is now the distance between the boy and his image? Give a reason for your answer. 

What must be the minimum length of a plane mirror in which a person can see himself full length? Draw a diagram to justify your answer. Does the distance of a person from the mirror affect the above answer?

An insect is sitting in front of a plane mirror at a distance of one meter from it.

1. Where is the image of insect formed?
2. What is the distance between insect and its image?
3. State any two characteristics of image formed in a plane mirror.

Parallel rays are incident:

1. on regular surface and
2. on irregular surface. In what respect do reflected rays in (1) differ from those of (2)?