Question 1.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
Answer :
Question 2.
Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.
Answer :
- Transparent objects: Air, water, a sheet of plane glass.
- Translucent objects: A sheet of polythene, smoke, fog, a sheet of cellophane, a wire mesh.
- Opaque objects: A piece of rock, a sheet of aluminium, a mirror, a wooden board, a CD, an umbrella, a wall, a sheet of carbon paper, a sheet of cardboard.
- Luminous objects: A piece of red hot iron, a lighted fluorescent tube, the flame of a gas burner, a lighted torch, kerosene stove, sun, firefly.
- Non-luminous objects: Include all
- transparent objects,
- translucent objects and
- opaque objects and moon.
Question 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 :
Yes, there are many things which give a circular shadow if held in one way and a rectangular shadow if held in another way. For example, a cylinder, a circular disc, etc.
Question 4.
In a completely dark room, if you hold up a mirror in front of you, you see a reflection of yourself in the mirror?
Answer :
No, we will not see the image because there is no light.