Ray Optics

JEE Main level, numerical answer, medium

108 of 295

Question 108 of 295

A light ray enters a solid glass sphere of refractive index μ=3\mu =\sqrt{3} at an angle of incidence 60∘60^{\circ}. The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is _____________.

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Answer: 90


Apply Snell's law at S_

1sin⁡60∘=3sin⁡r1\sin 60^{\circ}=\sqrt{3}\sin r
sin⁡r=12\sin r=\dfrac{1}{2}
r=30∘r=30^{\circ}
from geometry

r′=30∘{r}^{'}=30^{\circ}
Again apply snell's law on
S2{S}_{2}
3sinr′=1sine\sqrt{3}{sinr}^{'}=1sine
32=sine\dfrac{\sqrt{3}}{2}=sine
∴e=60∘∴e=60^{\circ}
from geometry

r′+θ+e=180∘{r}^{'}+\theta +e=180^{\circ}
θ=90∘\theta =90^{\circ}

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