Which of the following are dimensionless?
(a) acceleration due to gravity
(b) strain
(c) mach number
(d) refractive index
Answer & explanation
Correct answer: option 1
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 = $\frac{c}{v}=\frac{LT^{-1}}{LT^{-1}}=1$