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Physics - Geometrical Optics Question with Solution | TestHub

PhysicsGeometrical OpticsTIR/Prism and DispersionMedium2 minPYQ_2019
PhysicsMediumsingle choice

A transparent cube of sided, made of a material of refractive indexμ2, is immersed in a liquid of refractive indexμ1 ( μ1<μ2). A ray is incident on the faceABat an angleθ(shown in the figure). Total internal reflection takes place at the pointEon the faceBC.







Then,θmust satisfy

Question diagram: A transparent cube of side d , made of a material of refract

Options:

Answer:
A
Solution:

At surface (1)

μ1sinθ=μ2sinr    1

At surface (2)

μ1=μ2sin90-r

μ1=μ2cosr ...(2)

From equation (1) and (2)

sinθ=sinrcosr

sinθ=μ22-μ12μ2μ1μ2

sinθ=μ22μ12-1 

θ must satisfy,

θ<sin-1μ22μ12-1

Stream:JEESubject:PhysicsTopic:Geometrical OpticsSubtopic:TIR/Prism and Dispersion
2mℹ️ Source: PYQ_2019

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