Light Deviation in a Prism – Rankers Physics

Refraction by Prism: Practice Problem & Solution

Assertion (A): When white light passes through a prism, deviation of violet light is more than green light. Reason (R): In a prism average deviation is measured as deviation of yellow light.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Refraction by Prism. Understanding the underlying formula is key to arriving at the correct answer below:

Violet light has the highest refractive index in a prism, so it deviates most, hence (A) is true. Yellow light is generally used for average deviation calculations in dispersion, so (R) is true. However, (R) does not explain (A).

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