Page 59 - Science Class 6 Times Publication

Articial sources of light
The human-made devices which emit light as per our desire are called

articial source of light. Several electrical devices such as  lament

lamp, uorescent lamp, torch light, etc are capable of converting
electrical energy into light energy and are regarded as the arti cial
sources of light. Besides these, candles, tuki, lantern, pala, diyalo,

etc are also articial sources of light.

Candle CFL bulb Filament bulb Lantern Diyo

Luminous and non-luminous objects

The natural sources such as the sun, stars,  rey, etc emit light of

their own. Similarly, the articial sources emit light of their own
after they are turned on. Such objects are called luminous objects
because they emit light themselves. Hence, the bodies which emit
light of their own are called luminous bodies.

But the objects like book, table, house, tree, roads, etc do not have
light of their own. They become visible by reecting the light of the

luminous objects. Hence, the objects which do not have light of their

own but become visible by reecting the light of others are called
non-luminous objects. The moon is also a non-luminous body because
it does not have its own light . It shines at night by re ecting the
light of the sun.
Transparent, translucent and opaque substances

Activity 5.1

Place a burning candle on a table and try to see it by erecting a book
in front of you. Can you see the candle through the book ?
Now, remove the book and erect a piece of glass. Can you see the
candle through the glass ?

Times' Crucial Science and Environment 55 Book 6