Class 8 Science

Light

Extra Questions

Multiple Choice Questions

Question 1: A toy is placed at 10 cm in front of a plane mirror. What is the distance of image from the mirror?

  1. 20 cm
  2. 40 cm
  3. 10 cm
  4. 30 cm

Answer: (c) 10 cm

Question 2: A candle is 30 cm high. What is the height of its image in a plane mirror?

  1. 10 cm
  2. 15 cm
  3. 30 cm
  4. 45 cm

Answer: (c) 30 cm

Question 3: Which of the following works on the concept of multiple reflections?

  1. Telescope
  2. Binoculars
  3. Kaleidoscope
  4. Sunglasses

Answer: (c) Kaleidoscope

Question 4: How many cells are there in a Braille character?

  1. 12
  2. 9
  3. 3
  4. 6

Answer: (d) 6

Question 5: Which of the following is a tactile aid?

  1. Stylus
  2. Tactile strip
  3. Braille script
  4. All of the above

Answer: (d) All of the above

Question 6: The human eye can clearly see up to which distance?

  1. Infinity
  2. 1000 km
  3. 100 km
  4. 10 km

Answer: (a) Infinity

Question 7: The human eye cannot clearly see less than which distance?

  1. 2.5 cm
  2. 25 cm
  3. 15 cm
  4. 1.5 cm

Answer: (b) 25 cm

Question 8: Angle of incidence is 15°, then what is the angle of reflection?

  1. 15°
  2. 30°
  3. 45°
  4. 60°

Answer: (a) 15°

Question 9: Which of the following will produce a regular reflection?

  1. Gold plate
  2. Steel plate
  3. Pearl
  4. Mirror

Answer: (d) Mirror

Question 10: The colour of iris in a person is green. What is the colour of eye in that person?

  1. Blue
  2. Green
  3. Black
  4. Dark brown

Answer: (b) Green

Very Short Answer Type

Question 1: What is light?

Answer: Light is a form of energy. It helps in the sense of vision.

Question 2: What is reflection of light?

Answer: When light falls on a shiny surface, most of it bounces back. This phenomenon is called reflection of light.

Question 3: What is incident ray?

Answer: The ray of light falling on a reflecting surface is called incident ray.

Question 4: What is reflected ray?

Answer: The ray of light coming back from a reflecting surface is called reflected ray.

Question 5: What is normal?

Answer: The perpendicular on reflecting surface at the point of incidence is called normal.

Question 6: What is angle of incidence?

Answer: The angle between incident ray and normal is called angle of incidence.

Question 7: What is angle of reflection?

Answer: The angle between reflected ray and normal is called angle of reflection.

Question 8: What is the nature of image in plane mirror?

Answer: In a plane mirror, image is erect, virtual and of the same size as object, and is laterally inverted.

Question 9: What is persistence of vision?

Answer: An image stays on retina for 1/16 of a second. This is called persistence of vision.