Chapter Name: Refraction of Light At Plane Surfaces
Activity Name: Relation between angle of incidence and angle of refraction in Refraction of Light At Plane Surfaces
In this experiment, we explore the phenomenon of refraction of light as it passes through a semi-circular glass disc. By measuring the angles of incidence and angles of refraction, we aim to establish a relationship between them.
Additionally, we calculate the refractive index of glass using the obtained data. The experiment helps understand how light behaves when transitioning from one medium to another.
- Wooden plank covered with white chart
- Small black painted plank
- Semi-circular glass disc (thickness approximately 2cm)
- Laser light
Step by Step Procedure:
- Draw two perpendicular lines on the white chart, intersecting at a point O.
- Label one line as NN (normal) and the other as MM (interface between two media).
- Align the protractor along NN with its center at O, marking angles from 0° to 90° on both sides of NN.
- Place the semi-circular glass disc on MM, with its center coinciding with point O.
- Send a laser light along NN, allowing it to pass from air to glass through point O.
- Observe the path of the laser light on the other side of the glass disc.
- Measure the angles of incidence and angles of refraction for various incident angles (150°, 200°, 300°, 400°, and 500°) by observing the path of the laser light.
- Note down your observations in table format:
- Handle the glass disc carefully to avoid breakage.
- Ensure the laser light is pointed safely away from eyes and other people.
- Make accurate measurements using the protractor and scale for reliable results.
Lesson Learnt from Experiment:
Through this experiment, we learn that when light passes from a rarer medium (air) to a denser medium (glass), the angle of refraction (r) is less than the angle of incidence (i). The refracted ray also bends towards the normal in each case. The experiment also allows us to calculate the refractive index of glass and understand the principles of light refraction.