Physics - Geometrical Optics Question with Solution | TestHub

PhysicsGeometrical OpticsTIR/Prism and DispersionMedium2 minPDF

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Passage / Comprehension

A transparent plastic semicylinder has refractive index $μ = 2$ and radius R. A narrow light ray enters normally through the flat face at distance d from the symmetry axis, as shown.

When the value of d chosen is such that TIR just takes place then time for which light remains inside the cylinder is :- $(c =$ speed of light in vacuum $)$

Options:

Answer:

Solution:

At limiting TIR, the internal chord length is $2 R cos 4 5^{\circ} = 2 R$ .

The ray covers the corresponding repeated path shown in the semicylinder.

$t = \frac{4 R}{c}$

Hence option A.

Stream:JEESubject:PhysicsTopic:Geometrical OpticsSubtopic:TIR/Prism and Dispersion

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