In measurement− i. Relative error = absolute error / measured value ii. Vernier constant = (value of the smallest main-scale division) / (total number of divisions on the vernier scale) iii. Least count = (number of divisions of the circular scale) / pitch

Chattogram Board 2021

In measurement−

i. Relative error = absolute error / measured value
ii. Vernier constant = (value of the smallest main-scale division) / (total number of divisions on the vernier scale)
iii. Least count = (number of divisions of the circular scale) / pitch

Think it through first, then pick an option.

Answer and explanation

Correct answer: a i and ii

i is true (relative error = absolute error ÷ measured value); ii is true (VC = smallest main division ÷ number of vernier divisions); iii is false.

Why the other options are wrong

b i and iii: iii is false: least count = pitch ÷ circular divisions, not the other way round; ii is true but is left out of this option.
c ii and iii: i is true but is left out of this option; iii is false: least count = pitch ÷ circular divisions.
d i, ii and iii: iii is false: least count = pitch ÷ circular divisions, so not all three are true.