Q1. Fill in the Blanks:
Ans:
(a) An image that cannot be obtained on a screen is called virtual.
(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.
Q2. Mark ‘T’ if the statement is true and ‘F’ if it is false:
Ans:
(a) We can obtain an enlarged and erect image by a convex mirror. = (F)
(Convex mirror forms an erect & diminshed image.)
(b) A concave lens always forms a virtual image. = (T)
(c) We can obtain a real, enlarged, and inverted image by a concave mirror. = (T)
(d) A real image cannot be obtained on a screen. = (F)
(A real image can be obtained on the screen.)
(e) A concave mirror always form a real image. = (F)
(Concave mirror can form virtual images.)
Q3. Match the items given in Column I with one or more items of Column II.
Ans:
| 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 |
(v) The image is erect and of the same size as the object. |
| (c) A convex lens |
(i) Used as a magnifying glass. |
| (d) A concave mirror |
(iii) Used by dentists to see enlarged image of teeth. |
| (e) A concave lens |
vi) The image is erect and smaller in size than the object. |
Q4. State the characteristics of the image formed by a plane mirror.
Ans:
The image formed by the plane mirror is:
- Erect, virtual & laterally inverted (i.e. the image's left & right sides are reversed.)
- Same in size as the object.
- The image distance is the same as the object distance from the mirror.
Q5. Find out the letters of 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.
Ans:
Letters A, H, I, M, O, T, U, V, W, X and Y form the same image in a plane mirror as they are laterally symmetrical.
Q6. What is a virtual image? Give one situation where a virtual image is formed.
Ans:
- An image that cannot be formed on the screen is called as a virtual image.
- Virtual image is formed when reflected rays of light do not meet but appear to meet.
- The image formed in a plane mirror is virtual because the light rays appear to come from behind the mirror.
Q7. State two differences between a convex and a concave lens.
Ans:
| Convex lens |
Concave lens |
| It is thicker in the middle & thinner at the edges. |
It is thinner in the middle & thicker at the edges. |
| They are converging lenses as light rays appear to meet at a point. |
They are diverging lenses as they spread the light rays. |
| It can form magnified image. |
Image is always diminished in size. |
Q8. Give one use each of a concave and a convex mirror.
Ans:
Use of concave mirror: By dentists to examine the teeth.
Use of convex mirror: In side view mirror in vehicles.
Q9. Which type of mirror can form a real image?
Ans:
A concave mirror can form a real image.
Q10. Which type of lens forms always a virtual image?
Ans:
A concave lens always forms a virtual image.
Choose the correct option in questions 11–13
Q11. A virtual image larger than the object can be produced by a:
Ans: (ii) concave mirror
Q12. 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
Ans: (iii) 6 m
Q13. 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 rear view 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
Ans: (iii) 4 m/s
