## Chapter 11 Light, Shadows and Reflections

Question 1: Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
OPAQ QEO BJEC TSM AKE SHAD OWS

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.

• Opaque
→ 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.
• Transparent
→ Air, water, a sheet of plane glass.
• Translucent
→ A sheet of polythene, smoke, fog, a sheet of cellophane, a wire mesh.
• Luminous
→ A piece of red hot iron, a lighted fluorescent tube, the flame of a gas burner, a lighted torch, sun, firefly, kerosene stove.
• 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, an umbrella, a wall, a sheet of carbon paper, a sheet of cardboard, a sheet of cellophane, a wire mesh, 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?