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

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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°

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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.

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