Page 132 - Innovator's Science-8

Laws of Reflection

Look at the figure given previously again. You
will see the image of object A as A' and object
B as B'. Also i = r and i = r, i.e., angle of
incidence is always equal to the angle of

reflection. Also the incident ray, the reflected
ray and the normal all lie in the same plane.
Thus, we can summarise the two laws of Reflection of light in still water

reflection as given below:
• Law I: The incident ray, the reflected ray and the normal ray to the
reflecting surface lie in the same plane.

• Law II: The angle of incidence is equal to the angle of reflection.

The laws of reflection apply to all reflecting surfaces whether it is plane or
curved.

Given below are activities that will help us to study the reflection of light.

Activity-3 Aim: To show that a mirror reflects light and divert its path.
Materials Required: A plane mirror, a sheet of chart paper, a torch, a black-coloured
Experiential Learning
sheet of paper and a table
Procedure:

• Take a sheet of chart paper and fix it on a table.
• Place a mirror ver cally on the sheet.
• Take a torch and cover its lens with a black-
coloured sheet that has two holes in it.
• Place the torch at an angle to the mirror as Mirror reflects light
shown in the figure. and changes its path
• Switch on the torch and direct the beam of light on the mirror such that the
focussed light is seen on the chart paper.
Observa on: As the light rays strike the mirror, they are reflected in a different
direc on. This proves that mirror reflects light and changes its path.

Activity-4 Aim: To prove that smooth and shiny surfaces reflect light be er.
Materials Required: A torch, a mirror, a steel plate and a paper sheet.
Experiential Learning
Procedure: Shine a beam of light
through a torch on a mirror such that
the reflected light falls on the wall.

Now repeat the same process by
replacing the mirror with a steel plate
Mirror Steel plate Paper
and then with a sheet of paper. Reflec on of light by different objects

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Science-8