Question

A given ray of light suffers minimum deviation in an equilateral prism P. Additional prisms Q and R of identical shape and of the same material as P are now added as shown in the figure. The ray will suffer

• A. greater deviation
• B. no deviation
• C. same deviation as before
• D. total internal reflection

Answer 1

The Correct Option is C

To solve this problem, we need to understand the behavior of light as it passes through multiple identical prisms of the same material and shape. Below are the detailed steps and explanations:

Step 1: Understanding Minimum Deviation

A ray of light suffers minimum deviation in a prism when it passes symmetrically through the prism. For an equilateral prism, this occurs when the angle of incidence is equal on both sides and is such that the path of the ray within the prism is parallel to the base of the prism.

Step 2: Behavior in Additional Prisms of the Same Material and Shape

When additional prisms Q and R, which are identical to P, are added, the ray will continue to pass symmetrically through them due to the identical material and prism shape. By adding prisms of the same refractive index and shape, the angle of refraction and the path within each prism will remain unchanged.

Step 3: Resulting Deviation

Since the prisms are configured in the same way and are made of the same material, they maintain the initial conditions for minimum deviation. The overall path of light will therefore remain unchanged in terms of deviation. Thus, the ray will suffer:

Conclusion

The ray will experience the same deviation as before. This is because the symmetric arrangement of prisms made of the same material preserves the path and deviation characteristics of the light ray.