The form of energy that helps us to see things around us is light.
Natural Sources of Light
The Sun, stars, and lightening are some natural sources of light.
Artificial Sources of Light
The light from candle, oil lamp, electric bulb, LEDs and torchlight are some artificial sources of light.
When light leaves its source, it travels in straight lines in all the directions. The light can pass through some objects, but when light cannot pass through an object, a shadow of that object is formed behind it.
If someone has negative Lense in eyes then the role of light to see things diminishes.
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