In an optical fibre,the core and cladding are | vedclass

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(C) For an optical fibre,the acceptance angle $	heta_a$ is given by the formula: $\sin 	heta_a = \sqrt{\mu_1^2 - \mu_2^2}$,where $\mu_1$ is the refr

Vedclass · Accepted Answer

$0^{\circ}-30^{\circ}$

Vedclass · Answer

(C) For an optical fibre,the acceptance angle $	heta_a$ is given by the formula: $\sin 	heta_a = \sqrt{\mu_1^2 - \mu_2^2}$,where $\mu_1$ is the refractive index of the core and $\mu_2$ is the refractive index of the cladding,assuming the surrounding medium is air $(\mu_0 = 1)$.Given $\mu_1 = 1.5$ and $\mu_2 = 1.414$.Substituting the values: $\sin 	heta_a = \sqrt{(1.5)^2 - (1.414)^2}$.Since $(1.414)^2 \approx 2$,we have $\sin 	heta_a = \sqrt{2.25 - 2} = \sqrt{0.25} = 0.5$.Therefore,$	heta_a = \sin^{-1}(0.5) = 30^{\circ}$.This means the incident light must enter the fibre within an angle range of $0^{\circ}$ to $30^{\circ}$ with the axis to undergo total internal reflection.Hence,option $(C)$ is correct.

In an optical fibre,the core and cladding are made with materials of refractive indices $1.5$ and $1.414$ respectively. To observe total internal reflection,what will be the range of the incident angle with the axis of the optical fibre?

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