Refraction of Light

3.2.2 Refraction of light

Refraction is the bending of light as it passes from one transparent medium to another. This bending occurs because the speed of light changes when it enters a different medium. The amount of bending depends on the difference in the refractive indices of the two media and the angle at which the light strikes the surface.

Experiment: Investigating Refraction of Light by Transparent Blocks

This experiment aims to demonstrate the refraction of light by transparent blocks of different shapes and to observe how the angle of incidence affects the angle of refraction.

Apparatus

• A transparent block (e.g., glass or acrylic) with various shapes (e.g., rectangular, curved, prism-shaped).
• A light source (e.g., a torch or laser pointer).
• A screen or white paper.
• A protractor.
• A ruler.
• A drawing board or stable surface.
• A pencil.

Procedure

1. Set up the experiment on a drawing board. Place the transparent block on the board.
2. Position the light source so that a beam of light shines onto the transparent block.
3. Adjust the position of the screen so that the refracted light is clearly visible on it.
4. For each shape of the transparent block:
   1. Mark the point where the light beam enters the block.
   2. Mark the point where the light beam exits the block.
   3. Draw a line connecting the two marked points.
   4. Draw a line perpendicular to the surface of the block at the point where the light enters.
   5. Measure the angle of incidence (the angle between the perpendicular line and the incident beam) and the angle of refraction (the angle between the perpendicular line and the refracted beam) using a protractor.
   6. Repeat the measurements for several different positions of the light beam on the block's surface to obtain more reliable data.

Data Table

Shape of Block	Position of Light Beam	Angle of Incidence (degrees)	Angle of Refraction (degrees)
Rectangular	Near one end
Rectangular	Middle of one face
Rectangular	Near the other end
Curved	At the widest part
Prism-shaped	On one of the flat faces

Analysis

By comparing the angles of incidence and refraction for different shapes and positions of the light beam, you can observe how the shape of the transparent block affects the refraction of light. You should notice that the angle of refraction changes depending on the angle of incidence and the shape of the block. A curved block will cause more complex refraction patterns than a rectangular block.

Conclusion

Summarize your findings and state how the experiment demonstrates the refraction of light. Discuss any sources of error and suggest improvements to the experimental design.