Light is the energy that makes objects visible to naked eyes. Without light, we cannot see things. The objects that emit light are the sources of light.
These two sources of light
Natural sources of light come from naturally present things like the sun, stars, and fireflies.
The sun is a vital light source that is 150 million kilometers away from the Earth. It allows us to see objects in the daytime.
The light sources made by human beings are called artificial sources of light, and some examples are- torch, tube light, electric bulbs.
These light sources enable vision during the night.
The objects that can give out light of their own are called luminous objects, and a few examples are the sun, tube light, burning candles.
These objects can be seen even at night because they have the light that is their own.
The objects that cannot emit light are called non-luminous objects, and some examples are- a tree, book, moon.
The non-luminous objects cannot be visible in the darkness. The non-luminous things reflect light emitted by the luminous objects to make themselves visible.
The shadows are formed when light falls on an object. The dark shade that forms behind an object is called a shadow.
The shadows result because light travels in a straight line.
The light passes through transparent objects, and they do not cause shadows. Translucent objects partially allow light to pass through, and thus weak shadows are cast. Opaque objects do not allow light to pass through them and therefore are the main objects that cause shadows.
When an object sends back the light that falls on it, it is called a reflection.
Different objects reflect different amounts of light. Polished surfaces reflect better than unpolished ones.
The narrow beam of light that is responsible for reflection to occur is called a ray. The incident ray is the beam of light before, and the reflected ray is the light beam after it takes place.
There are two types of reflection.
Smooth and polished surfaces reflect light in the same direction. It is known as regular reflection.
The surfaces that are rough like paper reflect in all directions. These are called irregular reflections.