# NCERT Solutions for Class 7 Science Chapter 11 Light

NCERT Solutions Class 7 Science Chapter 11 Light is provided here to help students in understanding the topic thoroughly. All these solutions are solved by experts with a detailed explanation. Class 7 NCERT Solutions for Science Chapter 11 includes all the textbook exercise questions and answers. These solutions will help students complete their assignments & homework.

## Class 7 Science Light Questions and Answers

Exercise Questions

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.

(b) mirror
(c) plane
(d) real
(e) lens

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 form 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)

(a) False
(b) True
(c) True
(d) False
(e) False

Question 3: Match the items given in Column I with one or more items of Column II

Question 4 . State the characteristics of the image formed by a plane mirror.

Answer: Characteristics of the image formed by a plane mirror:
(i) The image formed is virtual
(ii) The image is laterally inverted.
(iii) It is of the same size as the object.
(iv) The image is situated at the same distance from the mirror as the object.
(v) The image is erected.

Question 5. 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.

Answer: If the letters of English alphabet A, H, I, M, O, T, U, V, W, X, Y are kept in front of a plane mirror, then they would form images which exactly look like the original letters of the alphabet. These letters are vertically symmetric. For example, if we divide letters A and U in the middle, then we would find that the right halves are equivalent to the left halves of the letters. Hence, even if the image interchanges sidewise, it will appear same as the letter

Question 6. What is a virtual image? Give one situation where a virtual image is formed.

Answer: The image which cannot be taken on a screen is called virtual image. When some object is placed very close to the concave mirror we don’t get any image on the white screen placed behind the mirror. Such image is called virtual image.

Question 7. State two differences between a convex and a concave lens.

Question 8. Give one use each of a concave and a convex mirror.

Answer: Concave mirrors can form enlarged image of the object. Therefore, they are used by the dentist to see the enlarged image of the patient’s teeth.

Convex mirror forms diminished and upright image of the object. It is used as a side view mirror of the car because it enables the driver to view objects spread over a large area behind him/her.

Question 9. Which type of mirror can form a real image?

Answer: Concave mirror can form a real image.

Question 10. Which type of lens forms always a virtual image?

Answer: Concave lens always 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

Question 12. David is observing his image in a plane mirror. Die 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

In the case of a plane mirror, the distance between the object and the mirror (d1) is same as the distance between the image and the mirror (d2).

Given,
Distance between the mirror and David’s image, d2 = 4 m
Therefore, d1 = d2 = 4 m
If David moves 1 m towards the mirror, then d1 = 4 − 1 = 3 m
Again, d1 = d2 = 3 m
Therefore, the distance between David and his image is d1 + d2 = 3 + 3 = 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 rear mew 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