Refraction Of Light
Chapter Name : Light-Reflection And Refraction |
Sub Topic Code : 101_10_10_03_03 |
Topic Name : Refraction Of Light |
|
Sub Topic Name : The Refractive Index |
|
Introduction
We know that when light enters into a different medium, its speed changes. This is due to the refractive index of that medium.
Pre-Requisites:
Introduction about refraction of light and laws of refraction.
Activity:
In the glass slab activity, measure the incident angle and refracted angle and find the refractive index of the glass.
Real Life Question:
“Why we see a pencil broken when we put that in half filled glass of water?” “Why does the speed of light change when it enters into glass from air?”
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Refractive Index | It is the ratio of the speed of light in air to the speed of light in any medium. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|
Real life uses :
Polymers are made of high refractive indices which are used for reflective coating. They are also used in LEDs.
Places to visit :
Your physics lab to the see the refractive indices of various mediums.
Practical examples around us
| Examples | Explainations |
|---|---|
| Twinkling of stars | When light from the stars passes through the various layers of the earth’s atmosphere, its speed changes and stars seem to be twinkling. |
| Mirages | A natural phenomenon in which we see the object displaced from its position due to difference in refractive indices of air and vacuum. |
What you learn in Theory:
Refractive index is a ratio of speed of light in air to the speed of light in any medium. Its value is different for the different mediums.
What you learn in Practice:
Speed of light changes when it changes the medium of propagation. And that angle of bending of light can be determined by the refractive index of that medium.