Class 7 Science


NCERT Solution Part 2

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

Answer: (a) Concave mirror is used in solar furnace.

(b) Convex mirror is used in rear view mirrors.

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

Answer: Concave mirror

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

Answer: Concave lens

Question 11: A virtual image larger than the object can be produced by a

  1. Concave lens
  2. Concave mirror
  3. Convex mirror
  4. Plane mirror

Answer: (c) 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

  1. 3 m
  2. 5 m
  3. 6 m
  4. 8 m

Answer: (a) 3 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 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

  1. 1 m/s
  2. 2 m/s
  3. 4 m/s
  4. 8 m/s

Answer: (b) 2 m/s