Chapter 11: Light, Shadows and Reflection (Solutions)
Posted on : 22-06-2018 Posted by : Admin

Link to Notes on this topic

1. Rearrange the boxes given below to make a sentence that helps us understand opaque objects

NCERT notes, free, CBSE notes, light, shadow, reflection, Transparent, opaque, translucent, pinhole camera, mirror, light travels in straight lines

   Answer:NCERT notes, free, CBSE notes, light, shadow, reflection, Transparent, opaque, translucent, pinhole camera, mirror, light travels in straight lines

2. Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:

Objects Opaque or Transparent or Translucent Luminous or Non-luminous
Air Transparent Non-Luminous
Water Transparent Non-Luminous
A piece of rock Opaque Non-Luminous
A sheet of aluminium Opaque Non-Luminous
A mirror Opaque Non-Luminous
A wooden board Opaque Non-Luminous
A sheet of polythene Translucent Non-Luminous
A CD Opaque Non-Luminous
Smoke Translucent Non-Luminous
A sheet of plane glass Translucent Non-Luminous
Fog Translucent Non-Luminous
A piece of red hot iron Opaque Luminous
An umbrella Opaque Non-Luminous
A lighted flourescent tube Opaque Luminous
A wall Opaque Non-Luminous
A sheet of carbon paper Opaque Non-Luminous
The flame of a gas burner Opaque Luminous
A sheet of cardboard Opaque Non-Luminous
A lighted torch Opaque Luminous
A sheet of cellophane Transparent Non-Luminous
A wire mesh - Non-Luminous
Kerosene stove Opaque Luminous
Sun Opaque Luminous
Firefly Opaque Luminous
Moon Opaque Non-Luminous

3. Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

Answer: 

NCERT notes, free, CBSE notes, light, shadow, reflection, Transparent, opaque, translucent, pinhole camera, mirror, light travels in straight lines

4. In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?

Answer: In a completely dark room, we cannot see our reflection in the mirror. This is because, a source of light is needed for the mirror to reflect the image. As there is no light in the room, there would not be any reflection of light and no image will be formed in the mirror.



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