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NEET 2026
Exam
NEET
Year
2026
Subject
Physics
Chapter
Chapter

NEET 2026 · Physics · Chapter

A narrow beam of light travelling in air strikes the flat surface...

A narrow beam of light travelling in air strikes the flat surface of a transparent liquid at an angle of incidence of 45∘45^{\circ}. If the refractive index of the liquid is 2\sqrt{2}, what is the angle of deviation suffered by the light ray upon refraction?

Options

  1. A30∘30^{\circ}
  2. B15∘15^{\circ}
  3. C75∘75^{\circ}
  4. D45∘45^{\circ}

Correct answer

B. 15∘15^{\circ}

Step-by-step solution

Using Snell's law at the air-liquid interface:

n1sin⁡i=n2sin⁡rn_1 \sin i = n_2 \sin r

Substituting the given values:

1×sin⁡45∘=2×sin⁡r1 \times \sin 45^{\circ} = \sqrt{2} \times \sin r

12=2sin⁡r\dfrac{1}{\sqrt{2}} = \sqrt{2} \sin r

sin⁡r=12\sin r = \dfrac{1}{2}

r=30∘r = 30^{\circ}

The angle of deviation δ\delta is given by:

δ=i−r\delta = i - r

δ=45∘−30∘=15∘\delta = 45^{\circ} - 30^{\circ} = 15^{\circ}

Answer: 15∘15^{\circ}
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