Exercise
Que1: Rearrange the boxes given below to make a sentence that helps us understand opaque object.
Ans:
Ques2: 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,b 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.
Ans:
Opaque : A piece of rock, a sheet of aluminium, a mirror, a wooden board, a CD, a piece of red hot iron, a umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of gas burner, a sheet of cardboard, a lighted tourch, kerosene stove, sun, firefly, moon.
Transparent: Air, water.
Translucent: A sheet of polythene, smoke, a sheet of plane gas, gas, a sheet of cellophone, a wire mesh.
Luminous: A piece of red hot iron, a lighted fluoressent tube, the flame of a gas burner, a lighted torch, sun, firefly.
Non - luminous: Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden, a sheet of carbon paper, a sheet of cardboard, a sheet of cellophone, a wire mesh, kerosene stove, moon.
Que3: 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?
Ans: A cylinder object can cast shadows in two ways. When the top circular view faces the shining object. a circular shape shadow is formed, When its curved side faces the shining object. it casts a rectangular shadow.
Que4: 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?
Ans: No, to see reflection, source of light is required. We can see only in the presence of light.
