Introduction

Source of light

Any object which emits light is called a source of light. The different source of light can be grouped as:

(a) Natural sources of light

(i) The Sun: The most vital and brightest source of natural light for the entire is the sun. It provides light and warmth for us on the earth.

(ii) The Moon: it is again a natural sources of light. It has no light of its own, but it reflects the light of the sun which spreads a cool and pleasant light at night.

(iii) The stars: Some stars shine brighter than the Sun and are natural sources of light, but being very far away are not visible to us. Others are visible to us as small twinkling ones.

(iv) Fire Flies: These are amazing creatures that are a natural source of light and  although they do not emit very bright light, they are very pleasing to the eyes.

(b) Artificial sources or Manmade sources of light

There are numerous sources of artificial light, but let us take some of them as examples:

(i) Candles, lamps (of all kinds e.g. gas, earthen etc)

(ii) Electric bulbs/ tubes I etc: these are the main sources of light in our days to day life be at home or out in the city.

How Objects Become Visible to Us

When light from a luminous body, like sun, electric light or torch falls on an object, it bounces off and travels to our eyes, thus, making the object visible.