Light

UNIT 3

LIGHT

Learning Objectives

After the completion of this lesson, students will be able to:

* acquire knowledge about various types of mirrors.

* understand image formation in spherical mirrors.

* know about the applications of spherical mirrors.

* acquire knowledge about laws of reflection.

* compare regular and irregular reflections.

* understand the working principle of kaleidoscope and periscope.

* understand refraction and dispersion of light

Introduction

Lofty mountains covered with greenish vegetation, magnificent trees reaching the clouds, beautiful streams drifting down the valleys, bluish sea water roaring towards the coast and the radiant sky in the morning being filled with golden red color, all give delight to our eyes and peace to our mind. But, can we see them all without light? No, because, we can see things around us only when the light reflected by them reaches our eyes. What is light?

Light is a form of energy and it travels in a straight line. You have studied in your lower classes, how it is reflected by the polished surfaces such as plane mirrors. This reflecting property of light is applied in various devises that we use in our daily life. In this lesson, you will study about types of mirrors like spherical mirrors and parabolic mirrors. You will also study about the laws of reflection and the laws of refraction and some of the optical instruments, such as periscope and kaleidoscope, which work on these principles.