Question

Consider following statements for refraction of light through prism, when angle of deviation is minimum.

• A. The refracted ray inside prism becomes parallel to the base.
• B. Larger angle prisms provide smaller angle of minimum deviation.
• C. Angle of incidence and angle of emergence becomes equal.
• D. There are always two sets of angle of incidence for which deviation will be same except at minimum deviation setting.

Hint:

Remember the conditions for minimum deviation in a prism. The refracted ray becomes parallel to the base, and the angle of incidence equals the angle of emergence.

Answer 1

The Correct Option is A

To determine which statements are true about the refraction of light through a prism at the minimum angle of deviation, let's explore the concept of light refraction through a prism and the conditions at minimum deviation:

1. The minimum angle of deviation occurs when the light travels symmetrically through the prism. This means that the angle of incidence at the first face of the prism is equal to the angle of emergence at the second face.
2. At the minimum deviation position, the refracted ray inside the prism is parallel to the base of the prism. Therefore, the correct answer is:
   • The refracted ray inside prism becomes parallel to the base
3. Consider the reasons why other options are incorrect:
   • Larger angle prisms provide smaller angle of minimum deviation: Generally, an increase in the prism angle results in a larger angle of minimum deviation, not smaller. So, this statement is incorrect.
   • Angle of incidence and angle of emergence becomes equal: This statement is actually correct at the point of minimum deviation, making it a valid condition of minimum deviation but not the most explanatory fact for the question asked.
   • There are always two sets of angle of incidence for which deviation will be same except at minimum deviation setting: This statement describes how deviation varies with incidence and emergence angles, but it emphasizes behavior except at the minimum deviation, which doesn't make it an insightful answer for the question.

In summary, the refracted ray being parallel to the base at the minimum deviation is indicative of the symmetric passing of light through the prism at this condition, thereby validating the correct choice.