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Question: Answered & Verified by Expert

Assertion (A): The focal length of lens does not change when red light is replaced by blue light.

Reason (R): The focal length of lens does not depend in colour of light used.

PhysicsRay OpticsAP EAMCETAP EAMCET 2021 (20 Aug Shift 2)
Options:
  • A Both A and R are true and R is a correct explanation for A
  • B Both A and R are true but R is not a correct explanation for A
  • C A is true, R is false
  • D Both A and R are false
Solution:
2807 Upvotes Verified Answer
The correct answer is: Both A and R are false

Focal length of the lens depends upon its refractive index as 1f∝μ-1.

Therefore, the focal length of a lens decreases when red light is replaced by blue light.

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