Assertion : In optical fibre, the diamet...

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

a.If both Assertion & Reason are true and the reason is the correct explanation of the assertion.

b.if both assertion and reason are true but reason is not the correct expalanation of the assertion

c.if assertion is true , but reason is false

d.both assertion and reason are false statements.

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The correct Answer is:

To solve the question, we need to analyze both the assertion and the reason provided. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that "In optical fibre, the diameter of the core is kept small." - This is true because a smaller core diameter allows for better confinement of light within the core, which is essential for the functioning of optical fibers. 2. **Understanding the Reason**: - The reason states that "This smaller diameter of the core ensures that the fibre should have an incident angle more than the critical angle required for total internal reflection." - For total internal reflection to occur, the angle of incidence must be greater than the critical angle. A smaller core diameter helps achieve this condition by allowing light rays to strike the core-cladding boundary at a steeper angle. 3. **Analyzing Total Internal Reflection**: - Total internal reflection occurs when light travels from a denser medium (core) to a rarer medium (cladding) and the angle of incidence exceeds the critical angle. - The critical angle is determined by the refractive indices of the core and cladding. For total internal reflection to happen, the refractive index of the core (μ1) must be greater than that of the cladding (μ2). 4. **Conclusion**: - Since both the assertion and reason are true, and the reason correctly explains the assertion, we conclude that the assertion is true and the reason is also true, providing a correct explanation for the assertion. ### Final Answer: - Both the assertion and reason are true, and the reason is a correct explanation of the assertion.

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

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