Question

Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle through which the emergent ray bends from the direction of the incident ray and also name it.

Hint:

The angle of deviation is the angle between the direction of the incident ray and the emergent ray after refraction through the prism.

Answer 1

The ray diagram is as follows:

To draw a ray diagram showing the refraction of a ray of light passing through an equilateral glass prism and to mark the angle through which the emergent ray bends from the direction of the incident ray, follow these steps:
1. Draw the Prism:
Sketch an equilateral triangle to represent the glass prism. Label the vertices as \( A \), \( B \), and \( C \).
2. Incident Ray:
Draw an incident ray approaching the prism at one of its faces (e.g., face \( AB \)). Label the point where the ray enters the prism as point \( P \).
3. Refraction at First Face:
At point \( P \), draw the refracted ray inside the prism. The ray bends towards the normal as it enters the denser glass medium from air.
4. Refraction at Second Face:
The refracted ray travels through the prism and reaches the second face (e.g., face \( AC \)). Label the point where the ray exits the prism as point \( Q \).
5. Emergent Ray:
At point \( Q \), draw the emergent ray leaving the prism. The ray bends away from the normal as it exits the denser glass medium into air.
6. Angle of Deviation:
Extend the incident ray and the emergent ray backwards (dotted lines) to show their original paths if there were no prism.
The angle between the extended incident ray and the emergent ray is called the angle of deviation, denoted as \( \delta \). Mark this angle clearly on your diagram.
7. Labeling:
Label the incident ray, refracted ray, emergent ray, and the angle of deviation \( \delta \).
The angle of deviation \( \delta \) is the measure of how much the emergent ray has bent from the direction of the incident ray due to the refraction through the prism. This angle depends on the angle of incidence, the material of the prism, and the wavelength of the light. By following these steps, you can create a detailed and accurate ray diagram illustrating the refraction of light through an equilateral glass prism and identify the angle of deviation.