Refraction Of Light
Chapter Name : Light-Reflection And Refraction |
Sub Topic Code : 101_10_10_03_07 |
Topic Name : Refraction Of Light |
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Sub Topic Name : Sign Convention For Spherical Lenses |
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Introduction
We follow a specific sign convention in the case of lenses in order to use the distances in the calculations.
Pre-Requisites:
Introduction about the Cartesian system of representation and sign convention used in the mirrors.
Activity:
Take a convex lens, place an object at the different positions on the principal axis of lens and record the results obtained and also comment on the sign of various distances.
Real Life Question:
“Why the image formed by the convex lens is always virtual?”
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
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Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Any spherical lens | Place the object at various positions and observe the image formed by the lens. |
Real life uses :
In camera, binoculars, telescopes, projectors, microscopes, sunglass lenses etc.
Places to visit :
Your physics lab is having lenses; also you can go to the optical showroom to see various kinds of lenses, a planetarium where you can observe the telescopes.
Practical examples around us
| Examples | Explainations |
|---|---|
| Spectacles | The glasses we use to wear to correct our vision is made up of lenses. |
| Camera | Camera uses the lens to focus on the object. |
What you learn in Theory:
We calculate the distances of object and image from the optical center by following some rules of sign convention.
What you learn in Practice:
Lenses refract light falling on it. That’s why it is used in various optical instruments. A optician gives us the lenses to correct our vision.