Question 1. Fill in the blanks:
(a) An image that cannot be obtained on a screen is called ____________.
(b) Image formed by a convex __________ is always virtual and smaller in size.
(c) An image formed by a __________ mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a _________ image.
(e) An image formed by a concave ___________ cannot be obtained on a screen.
Solution 1.
(a) An image that cannot be obtained on a screen is called a virtual image.
(b) Image formed by a convex mirror is always virtual and smaller in size.
(c) An image formed by a plane mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a real image.
(e) An image formed by a concave lens cannot be obtained on a screen.
Question 2. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) We can obtain an enlarged and erect image by a convex mirror. (T/F)
(b) A concave lens always forms a virtual image. (T/F)
(c) We can obtain a real, enlarged and inverted image by a concave mirror. (T/F)
(d) A real image cannot be obtained on a screen. (T/F)
(e) A concave mirror always form a real image. (T/F)
Solution 2.
a) We can obtain an enlarged and erect image by a convex mirror. False
b) A concave lens always forms a virtual image. True
c) We can obtain a real, enlarged and inverted image by a concave mirror. True
d) A real image cannot be obtained on a screen. False
e) A concave mirror always forms a real image. False
Question 3. Match the items given in Column I with one or more items of Column II.
| Column-I | Column-II |
| (a) A plane mirror | (i) Used as a magnifying glass |
| (b) A convex mirror | (ii) Can form image of objects spread over a large area. |
| (c) A convex lens | (iii) Used by dentists to see enlarged image of teeth. |
| (d) A concave mirror | (iv) The image is always inverted and magnified |
| (e) A concave lens | (v) The image is erect and of the same size as the object. |
| (vi) The image is erect and smaller in size than the object. |
Solution 3.
| Column-I | Column-II |
| (a) A plane mirror | (v) The image is erect and of the same size as the object. |
| (b) A convex mirror | (ii) Can form an image of objects spread over a large area. |
| (c) A convex lens | (i) Used as a magnifying glass |
| (d) A concave mirror | (iii) Used by dentists to see an enlarged image of teeth. |
| (e) A concave lens | (vi) The image is erect and smaller in size than the object. |
Question 4. State the characteristics of the image formed by a plane mirror
Solution 4. The following are the characteristics of the image formed by a plane mirror:
- The distance between the object and the mirror is equal to the distance between the mirror and the image formed.
- The object and image formed are of equal size.
- An erect and virtual image is formed.
- Laterally inverted images are formed.
Question 5. Find out the letters of the English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.
Solution 5. Following are the letters of the English alphabet in which the image formed in a plane mirror appears exactly like the letter itself
A, H, I, M, O, T, U, V, W, X, Y
Question 6. What is a virtual image? Give one situation where a virtual image is formed.
Solution 6. An image that cannot be obtained on a screen is known as a virtual image. An image of an object formed by a concave mirror placed very close to it is called a virtual image.
Question 7. State two differences between a convex and a concave lens.
Solution 7.
| Convex Lens | Concave Lens |
| Thin at the edge and thick in the middle | Thin at the middle and thick at the edge |
| The image formed can be real or virtual | The image formed is always virtual |
Question 8. Give one use each of a concave and a convex mirror.
Solution 8. Use of concave mirror
In the headlights of cars and scooters.
Use of convex mirror
In the side-view mirrors in vehicles.
Question 9. Which type of mirror can form a real image?
Solution 9. The concave mirror can form a real image.
Question 10. Which type of lens forms always a virtual image?
Solution 10. The concave lens forms a virtual image.
Choose the correct option in questions 11–13
Question 11. A virtual image larger than the object can be produced by a
(i) concave lens (ii) concave mirror
(iii) convex mirror (iv) plane mirror
Solution 11.
(ii) concave mirror
Question 12. David is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be
(i) 3 m (ii) 5 m
(iii) 6 m (iv) 8 m
Solution 12.
(iii) 6 m
Question 13. The rear-view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rearview mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be
(i) 1 m/s (ii) 2 m/s
(iii) 4 m/s (iv) 8 m/s
Solution 13.
(iii) 4 m/s