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Refer figure. Core has refractive index ...

Refer figure. Core has refractive index `mu_(1)=1.424`. The cladding refractive index `mu_(2)=1.39`. In such a case. Will the light beam propagate?

A

Yes

B

No

C

Data given insufficient to decide

D

the beam propagation is not affected with refractive indices of fibre core and cladding.

Text Solution

Verified by Experts

The correct Answer is:
A
If `mu_(1)` is the refractiv e index of c ore of optical fibre, then
`mu_(1)=(sin 10^( o))/(sin7^(o))=(0.1736)/(0.1219)=1.424`
Critical angle at core and cladding surface in
`sin C=(mu_(2))/(mu_(1))=(1.39)/(1.424)=0.9761=sin 77^(@)27'`
`C=77^(@)7`'
The angle of incidence on core-cladding surface `= 90^(@)-7^(@)=83^(@)`, which is greater than critical single, hence beam will propagation through optical fibre.
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