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

Two plane mirrors are placed making an angle θ° in between them. For an object placed in between the mirrors, if angle is gradually increased from 0° to 180°, how will the number of images change : increase, decrease or remain unchanged?

How many images are formed for a point object kept in between two plane mirrors at right angles to each other? Show them by drawing a ray diagram. 

Two plane mirrors are arranged parallel and facing each other at some separation. How many images are formed for a point object kept in between them? Show the formation of images with the help of a ray diagram 

State two uses of a plane mirror. 

Two plane mirrors are placed making an angle 60° in between them. For an object placed in between the mirrors, the number of images formed will be :

In the barber's shop, two plane mirrors are placed :

An object is placed (i) asymmetrically (ii) symmetrically, between two plane mirrors inclined at an angle of 50°. Find the number of images formed.

Electromagnets are made up of :

The strength of the electromagnet can be increased by

Name the material used for preparing an electromagnet.

How is an electromagnet made? Name two factors on which the strength of magnetic field of the electromagnet depends.

You are required to make an electromagnet from a soft iron bar by using a cell, an insulated coil of copper wire and a switch.

1. Draw a circuit diagram to represent the process.
2. Label the poles of the electromagnet.

The following figure shows a coil wound around a soft iron bar XY.

1. State the polarity at the ends X and Y as the switch is pressed.
2. Suggest one way of increasing the strength of electromagnet so formed.

A coil of insulated copper wire is wound around a piece of soft iron and current is passed in the coil from a battery. What name is given to the device so obtained? Give one use of the device mentioned by you.

Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.

State two ways through which the strength of an electromagnet can be increased. 

Name one device that uses an electromagnet.

State two advantages of an electromagnet over a permanent magnet.

State two differences between an electromagnet and a permanent magnet.

Why is soft iron used as the core of the electromagnet in an electric bell?