AIIMS2018Physics-Optics

AIIMS 2018 Physics Dispersion and Refractive Index Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 12

Assertion : Dispersion of light occurs because velocity of light in a material depends upon its colour.

Reason : The dispersive power depends only upon the material of the prism, not upon the refracting angle of the prism.

A

Both statements are true and reason is the correct explanation of assertion.

B

Both statements are true but reason is not the correct explanation of assertion.

C

Assertion is true but reason is false.

D

Both assertion and reason are false.

Correct Answer

Option D

Detailed Explanation

Option D is correct because the assertion that "the dispersive power does not depend on prism angle" is false; in reality, the angle of the prism affects the dispersion of light. Additionally, the reason provided, which states that speed changes lead to dispersion, is misleading as dispersion primarily arises from the wavelength dependence of refractive index, not solely from speed changes. Other options are incorrect because they either misinterpret the relationship between the assertion and reason or incorrectly affirm their validity. Understanding that dispersion is influenced by both the material's refractive index and the geometry of the prism is crucial for grasping optical phenomena.

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