Light Shadows and Reflections - NCERT - NCERT Questions
Rearrange the boxes given below to make a sentence that helps us to understand opaque objects.
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.
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?
SOLUTION:When light falls on a cylinder sideways, then the shadow formed is rectangular.
When light falls on the top of a cylinder, then the shadow formed is circular.
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?
SOLUTION:In a completely dark room, there is no source of light. Thus, no light will get reflected from the surface of plane mirror. An image is formed due to reflection of light by a plane mirror. Hence, we will not see our reflection in the mirror.