Topic 3: Refractive Index (Absolute & Relative)

Q1. Absolute refractive index of a medium is given by:
A) v / c
B) c / v
C) c × v
D) c − v

Answer: B


Q2. Refractive index of vacuum is:
A) 0
B) 1
C) 1.33
D) 1.5

Answer: B


Q3. Relative refractive index of medium 2 with respect to medium 1 is:
A) v2 / v1
B) v1 / v2
C) c / v
D) sin r / sin i

Answer: B


Q4. Medium with higher refractive index is:
A) Optically rarer
B) Optically denser
C) Same as air
D) Vacuum

Answer: B


Q5. Refractive index of a medium depends on:
A) Shape of medium
B) Size of medium
C) Nature of medium
D) Distance travelled

Answer: C


Q6. If speed of light decreases in a medium, refractive index:
A) Decreases
B) Becomes zero
C) Remains same
D) Increases

Answer: D


Q7. Refractive index has:
A) Unit
B) Dimension
C) No unit
D) kg unit

Answer: C


Q8. Refractive index can be written in terms of angles as:
A) sin r / sin i
B) cos i / cos r
C) sin i / sin r
D) tan i / tan r

Answer: C

Chapter 13: Refraction of Light

Topic 3: Refractive Index – Quick Revision

1. Absolute Refractive Index

μ = c / v

2. Relative Refractive Index

μ₂₁ = v₁ / v₂

3. In Terms of Angles

μ = sin i / sin r

4. Key Points

• Higher μ → optically denser medium
• Speed of light decreases in denser medium
• Refractive index has no unit

Exam Focus (MHT-CET)

Numericals and MCQs are frequently asked on absolute & relative refractive index and formulas.