JEE Main 2022 · 27 Jun · Shift 1 · Physics Q47

← JEE Main 2022 · 27 Jun · Shift 1

PhysicsSingle correct+4 / -1Question 47 of 90

Consider a light ray travelling in air is incident into a medium of refractive index $\sqrt{2n}$ . The incident angle is twice that of refracting angle. Then, the angle of incidence will be :

\sin^{-1}\left(\sqrt n\right)

\cos^{-1}\left(\sqrt{\dfrac n2}\right)

\sin^{-1}\left(\sqrt{2n}\right)

2\cos^{-1}\left(\sqrt{\dfrac n2}\right)

Answer and worked solution

Official answer: D

Snell. $\sin i=\sqrt{2n}\sin\frac i2$ , i.e. $2\sin\frac i2\cos\frac i2=\sqrt{2n}\sin\frac i2$ , so $\cos\frac i2=\sqrt{\frac n2}$ .

Angle. $i=2\cos^{-1}\sqrt{\dfrac n2}$ .

(D)

Topics:Refraction at plane surfaces

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JEE Main 2022 · 27 Jun · Shift 1, Physics question 47