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AIIMS2015PhysicsRay Optics

Assertion : In optical fibre, the diameter of the core is kept small. Reason : The smaller diameter of the core ensures that the fibres should have incident angle more than the critical angle required for total internal reflection.

Options

  1. AIf both assertion and reason are true and reason is the correct explanation of assertion.
  2. BIfboth assertion and reason are true but reason is not the correct explanation of assertion.
  3. CIf assertion is true but reason is false.
  4. DIf both assertion and reason are false.

Correct answer

C. If assertion is true but reason is false.

Step-by-step solution

Diameter of a single mode optical fibre lies between 8 to 10.5 m Critical angle for total internal reflection does not depend on width of media.

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