Reflection and Refraction of Light
Why does light change direction when it refracts?
Eeshan threw the football towards the wall and it bounced back. “What did I do?” he asked.
“The football bounced back after you threw it on the wall,” Nitin answered with a puzzled expression.
“This is reflection,” said Eeshan. He continued, “The bouncing back of rays of light from a polished and shiny surface is called reflection or reflection of light. A mirror is a shiny polished object, which reflects most of the rays of light falling upon it. It is the reflection of light, which enables us to see any object.
When waves undergo reflection the angle the incoming waves make with the surface is equal to the angle of the reflected waves. This is what is the Law of Reflection and can be written as: The angle of incidence = the angle of reflection.”
“The change of direction of light because of a change of medium is known as Refraction of Light.” Eeshan rolled the football on the floor. It went fast on the smooth surface of the room but rolled slowly when it reached the balcony as the stones on the floor reduced its speed.
“Now this football not only changed its direction but also its speed on the balcony floor. Similarly, light travels with different speeds in different places. The ray of light changes its direction or refraction takes place because of the difference in speeds in different media.
Refraction is why water appears shallower than it really is.”
“Where do we use this?” Nitin asked.
Eeshan answered, “Well, you are able to see yourself in the mirror because of reflection. Spectacles make use of refraction to correct the vision of people who are nearsighted or farsighted. This is also used in telescopes. Did you understand?”
“Yes, Eeshan. Thank you!” said Nitin.
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