JEE Main 2022 · 29 Jun · Shift 2 · Physics Q34

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PhysicsSingle correct+4 / -1Question 34 of 90

The speed of light in media 'A' and 'B' are $2.0\times10^{10}$ cm/s and $1.5\times10^{10}$ cm/s respectively. A ray of light enters from the medium B to A at an incident angle ' $\theta$ '. If the ray suffers total internal reflection, then

\theta=\sin^{-1}\left(\dfrac34\right)

\theta>\sin^{-1}\left(\dfrac23\right)

\theta<\sin^{-1}\left(\dfrac34\right)

\theta>\sin^{-1}\left(\dfrac34\right)

Answer and worked solution

Official answer: D

Critical angle from B (slower) to A: $\sin C=\dfrac{v_B}{v_A}=\dfrac34$ . Total internal reflection needs $\theta>\sin^{-1}\frac34$ .

(D)

Topics:Total internal reflection

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JEE Main 2022 · 29 Jun · Shift 2, Physics question 34