English Medium Class 10 - CBSE Question Bank Solutions

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper. 

 At which point of the spherical mirror the carbon paper is placed?

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper. 

What name is given to the distance between spherical mirror and carbon paper?

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper. 

 What is the advantage of using a carbon paper rather than a white paper?

Complete the following sentence: 

All the distances are measured from the .......... of a spherical mirror. 

Write the mirror formula. Give the meaning of each symbol which occurs in it.

Name the spherical mirror which can produce a real and diminished image of an object.

Name the spherical mirror which can produce a virtual and diminished image of an object.

The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror: 

 What will be the focal length of this mirror?

The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror: 

 Which type of spherical mirror will it provide? 

The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror:

1. What will be the focal length of this mirror?
2. Which type of spherical mirror will it provide?
3. State whether this spherical mirror will diverge or converge light rays.

Write the formula for a lens connecting image distance (v), object distance (u) and the focal length (f). How does the lens formula differ from the mirror formula?

A lens forms a real image 3 cm high of an object 1 cm high. If the separation of object and image is 15 cm, find the focal length of the lens.

A diverging lens is used in ______.

A 50 cm tall object is at a very large distance from a diverging lens. A virtual, erect and diminished image of the object is formed at a distance of 20 cm in front of the lens. How much is the focal length of the lens?

A 2.0 cm tall object is placed 40 cm from a diverging lens of focal length 15 cm. Find the position and size of the image.

1. A small object is placed 150 mm away from a diverging lens of focal length 100 mm.
   1. Copy the figure below and draw rays to show how an image is formed by the lens.
      
   2. Calculate the distance of the image from the lens by using the lens formula.
2. The diverging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the diverging lens in part (a).

 The diverging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the diverging lens in part (a).

A concave lens produces an image 20 cm from the lens of an object placed 30 cm from the lens. The focal length of the lens is:
(a) 50 cm
(b) 40 cm
(c) 60 cm
(d) 30 cm

Define the following terms in the context of spherical mirrors :
(i) Pole

(ii) Centre of curvature

(iii) Radius of curvature

(iv) Principal axis

An optical device has been given to a student and he determines its focal length by focusing the image of the sun on a screen placed 24 cm from the device on the same side as the sun. Select the correct statement about the device. 
(A) Convex mirror of focal length 12 cm
(B) Convex lens of focal length 24 cm
(C) Concave mirror of focal length 24 cm
(D) Convex lens of focal length 12 cm