CLASS 7 LIGHT

..........can be defined as an invisible energy which causes the sensation of vision.

• LIGHT

• RECTILINEAR PROPOGATION

An object which is capable of giving out light is called a

• LIGHT

• SOURCE OF LIGHT

light is essential for our survival as..............

• we depend directly or indirectly on plants for food.

• s we depend only directly on plants for food.

Sun, the stars and the glow-worm are examples of

• natural soucres of light

• artificial sources of light

Candles, oil lamps, electric lights, fluorescent lamp (tube light) are made by humans and are called ..........

• natural sources of light

• artificial sources of light

All objects that emit their own light are called ............ Objects like stones, books etc that do not emit their own light are called non-luminous objects.

• luminous objects........non-luminous objects.

• non-luminous objects......luminous objects

moon is a non-luminous body but we are able to see it as ....................

• it reflects the light from the Sun that falls on it

• it reflects the light from the moon itselfthat falls on it

• it reflects own light

living bodies are fireflies, certain species of jelly fish, sea pansies, certain bacteria, algae and fungi are examples of

• bioluminescence

• chemiluminescence.

glow stick emits light without an electrical power source are examples of

• bioluminescence

• chemiluminescence

The emission of light by living bodies is called .............

• chemiluminescence

• bioluminescence