# NCERT Solutions for Class 7 Science Chapter 15 Light

Written by Team Trustudies
Updated at 2021-05-07

## NCERT solutions for class 7 Science Chapter 15 Light Exercise

Q.1 Fill in the blanks:
(a) An image that cannot be obtained on a screen is called ___________.
(b) Image formed by a convex _________ 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.

NCERT Solutions for Class 7 Science Chapter 15 Light

(a) An image that cannot be obtained on a screen is called virtual image.

(b) Image formed by a convex mirror 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.

Q.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)

NCERT Solutions for Class 7 Science Chapter 15 Light

(a) We can obtain an enlarged and erect image by a convex mirror. (F)

(b) A concave lens always form 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)

(e) A concave mirror always form a real image. (F)

Q.3 Match the items given in Column I with one or more items of Column II.

##### Column I
(a) A plane mirror
(b) A convex mirror
(c) A convex lens
(d) A concave mirror
(e) A concave lens
##### Column II
(i) Used as a magnifying glass.
(ii) Can form image of objects spread over a large area
(iii) Used by dentists to see an enlarged image of teeth
(iv) The image is always inverted and magnified.
(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.

NCERT Solutions for Class 7 Science Chapter 15 Light

(a) A plane mirror $$\rightarrow$$ (v) The image is erect and of thesame size as the object.

(b) A convex mirror $$\rightarrow$$ (ii) Can form image of objectsspread over a large area

(c) A convex lens $$\rightarrow$$ (i) Used as a magnifying glass.

(d) A concave mirror $$\rightarrow$$ (iii) Used by dentists to see an enlarged image of teeth

(e) A concave lens $$\rightarrow$$ (vi) The image is erect and smaller in size than the object.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

Characteristics of the image formed by a plane mirror are as follows :

(1) Image distance and object distance are equal.

(2) The size of the object and image are equal.

(3) The image formed is erect and virtual.

(4) Images are laterally inverted.

(5) Image is formed behind the mirror. .

Q.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.

NCERT Solutions for Class 7 Science Chapter 15 Light

If the letters of the 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 because these alphabets are laterally symmetric.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

(1) The image that cannot be obtained on a screen is called a virtual image.

(2) A virtual image is formed when reflected rays appear to meet.

(3) Plane mirrors, convex mirrors, and concave lenses always form virtual images.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

CONVEX LENS :

(1) Convex lens is thicker at the middle than edges.

(2) Convex lens converged the light ray falling on it.

(3) Image formed is real or virtual.

CONCAVE LENS :

(1) Concave lens is thinner at the middle than edges.

(2) Concave lens diverges the light ray falling on it.

(3) Image formed is virtual.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

(1) Concave mirrors are used in the headlights of cars and scooters, solar furnace, reflector of a torch, etc.

(2) Convex mirrors are used as side-view mirrors in vehicles.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

The concave mirror can form a real image.

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

NCERT Solutions for Class 7 Science Chapter 15 Light

Concave lens form a virtual image.

Q.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

NCERT Solutions for Class 7 Science Chapter 15 Light

(ii) concave mirror

Q.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

NCERT Solutions for Class 7 Science Chapter 15 Light

(iii) 6 m

Solution :

Initially, David is standing in front of the mirror. The distance between the mirror and his image= 4m.

David moves 1m towards the mirror. The distance of David from the mirror will be 3m.

The distance of the image from the mirror = 3m.

Therefore the distance between David and his image= 3m + 3m =6m.

Q.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

NCERT Solutions for Class 7 Science Chapter 15 Light

(ii) 2 m/s

Solution :

As the car moves 2m backward, the mirror also moves 2m backward, so the image comes 2m forward.

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