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Light
We see things clearly around us only when KEY CONCEPTS
there is enough light. Light is a form of
energy that makes objects visible to our eyes. • Luminous and non-luminous objects
• Sources of light
Without light, we cannot see things around
• Properties of light
us. For example, we cannot see things that
• Transparent, translucent and opaque
are kept in a dark room. Let’s learn more materials
about light in this chapter. • Formation of shadows
Luminous and Non-luminous Objects
Objects that emit light of their own are called luminous objects. The sun, stars, torch,
bulb, candle, and lamp are some luminous objects that emit light on their own. Some
of these objects like the sun and the stars are natural while others like lamp, candle and
torch are man-made sources of light. Most luminous objects like the sun, the stars and
the candle fl ames, produce light together with a large amount of heat.
sun stars torch bulb candle lamp
Some luminous objects
Objects that refl ect light of luminous objects are called non-luminous objects. The
moon, tree, chair, table, glass and pencil are some examples of non-luminous objects.
Non-luminous objects become visible only when light falls on them.
moon tree chair table glass pencil
Some non-luminous objects
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