Which of the following are dimensionless

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Target Exam

CUET

Subject

Physics

Chapter

Units and Measurements

Question:

Which of the following are dimensionless?
(a) acceleration due to gravity
(b) strain
(c) mach number
(d) refractive index

Options:

b, c, d

c, d

a, d

a, c, d

Correct Answer:

b, c, d

Explanation:

The correct answer is Option (1) → b, c, d

Strain, $e=\frac{Δl}{l}=\frac{L}{L}=1$

Mach number = $\frac{v_0}{v}=\frac{LT^{-1}}{LT^{-1}}=1$

Refractive index = $\frac{c}{v}=\frac{LT^{-1}}{LT^{-1}}=1$