Refraction & Total Internal Reflection — NEET Physics practice

Question 1

Three parallel-sided transparent slabs A, B and C of refractive indices n₁, n₂ and n₃ are placed side by side. A ray is incident at angle θ on the A–B interface; after refraction into B it just grazes the B–C interface. Then sin θ equals:

Accepted Answer

n₃/n₁

Answer

n₂/n₁

Answer

n₁/n₃

Answer

n₁/n₂

Question 2

The refractive index of the atmosphere decreases with height. Sowmya draws a ray starting nearly horizontal and curving progressively upward (towards the vertical). Leela draws a ray that starts rising and curves progressively towards the horizontal. Who is correct?

Accepted Answer

Leela is correct

Answer

Sowmya is correct

Answer

Both are correct

Answer

No conclusion can be drawn

Question 3

A ray is incident on a second medium at angle i and refracts at angle r. The graph of sin i (y-axis) vs sin r (x-axis) is a straight line through the origin at 60° to the x-axis. If the speed of light in the first medium is n times that in the second, n equals:

Accepted Answer

√3

Answer

2/√3

Answer

1/√3

Answer

√3/2

Question 4

A layer of ice (μ = 1.33 ≈ 4/3) lies on a glass plate (μ = 1.5). A ray from air is incident at 60° on the ice, refracting at r₁ into ice and at r₂ into glass. Match Column I with Column II. Column I: sin r₁; sin r₂; Refractive index of ice with respect to glass Column II: 1/√3; 3√3/8; 8/9

Accepted Answer

A→Q, B→P, C→R

Answer

A→P, B→Q, C→R

Answer

A→Q, B→R, C→P

Answer

A→P, B→R, C→Q

Question 5

A monochromatic wave (wavelength λ₁, frequency ν₁ in air) enters another medium with angles of incidence 45° and refraction 30°. The wavelength λ₂ and frequency ν₂ of the refracted wave are:

Accepted Answer

λ₂ = λ₁/√2, ν₂ = ν₁

Answer

λ₂ = √2·λ₁, ν₂ = ν₁

Answer

λ₂ = λ₁, ν₂ = √2·ν₁

Answer

λ₂ = λ₁, ν₂ = ν₁/√2

Question 6

Read the Assertion and Reason carefully and choose the correct option. Assertion: Light travels in a straight line when it moves through a homogeneous medium. Reason: The wavelength of light is very small compared to the size of ordinary objects.

Accepted Answer

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Answer

Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

Answer

Assertion is true, but Reason is false.

Answer

Assertion is false, but Reason is true.

Question 7

Read the Assertion and Reason carefully and choose the correct option. Assertion: When light travels from an optically denser to a rarer medium, it bends away from the normal. Reason: The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for a given pair of media.

Accepted Answer

Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

Answer

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Answer

Assertion is true, but Reason is false.

Answer

Assertion is false, but Reason is true.

Question 8

Read the Assertion and Reason carefully and choose the correct option. Assertion: Total internal reflection occurs when the angle of incidence in the denser medium is greater than the critical angle. Reason: The critical angle is the angle of incidence in the denser medium for which the angle of refraction is 90°.

Accepted Answer

Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

Answer

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Answer

Assertion is true, but Reason is false.

Answer

Assertion is false, but Reason is true.

Question 9

Read the Assertion and Reason carefully and choose the correct option. Assertion: When light undergoes total internal reflection, some of the light is transmitted into the second medium. Reason: During total internal reflection, all the light is reflected back into the denser medium and none is transmitted into the rarer medium.

Accepted Answer

Assertion is false, but Reason is true.

Answer

Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Answer

Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

Answer

Assertion is true, but Reason is false.

Question 10

Read Statement A and Statement B carefully and choose the correct option. Statement A: The speed of light in vacuum is the universal speed limit in nature. Statement B: The accepted value of the speed of light in vacuum is exactly 3 × 10⁸ m/s.

Accepted Answer

Statement A is true, but Statement B is false.

Answer

Both Statement A and Statement B are true.

Answer

Statement A is false, but Statement B is true.

Answer

Both Statement A and Statement B are false.

Question 11

Read Statement A and Statement B carefully and choose the correct option. Statement A: Total internal reflection can be used to trap light within a medium. Statement B: Optical fibres work on the principle of refraction, not total internal reflection.

Accepted Answer

Statement A is true, but Statement B is false.

Answer

Both Statement A and Statement B are true.

Answer

Statement A is false, but Statement B is true.

Answer

Both Statement A and Statement B are false.

Question 12

Match the terms related to refraction (Column I) with their descriptions (Column II). Column I: Snell's law; Refractive index (n₂₁); Optically denser medium; Angle of refraction (r) Column II: Less than the angle of incidence if n₂₁ > 1; Medium in which light bends towards the normal after refraction; Constant for a given pair of media and wavelength; Relates the angles of incidence and refraction with refractive indices

Accepted Answer

A→S, B→R, C→Q, D→P

Answer

A→R, B→S, C→P, D→Q

Answer

A→Q, B→P, C→S, D→R

Answer

A→S, B→R, C→P, D→Q

Question 13

Match the terms related to total internal reflection (Column I) with their descriptions (Column II). Column I: Total internal reflection; Critical angle (i꜀); Snell's law; Refractive index (n₂₁) Column II: Relation between the angles of incidence and refraction; Less than one when light travels from a denser to a rarer medium; Occurs when the angle of incidence exceeds the critical angle; Angle of incidence for which the angle of refraction is 90°

Accepted Answer

A→R, B→S, C→P, D→Q

Answer

A→S, B→P, C→R, D→Q

Answer

A→Q, B→S, C→P, D→R

Answer

A→R, B→S, C→Q, D→P

Question 14

When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same:

Accepted Answer

Frequency

Answer

Wavelength

Answer

Velocity

Answer

Amplitude

Refraction & Total Internal Reflection: NEET practice questions

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