Question

A vernier callipers having 1 main scale division = 0.1 cm is designed to have a least count of 0.02 cm. Let n be the number of divisions on vernier scale and m be the length of vernier scale, then which of the following is correct?

• A. n = 10, m = 0.5 cm
• B. n = 9, m = 0.4 cm
• C. n = 5, m = 0.8 cm
• D. n = 10, m=0.2 cm

Answer 1

Answer: (C)

Least count of vernier calliper is,
$LC=\frac{1MSD}{no.ofdivisionsonvernier}$
So $0.02=\frac{0.1}{n}$
We get n = 5
∴ $LC=1MSD-1VSD$
So, 0.02 = 0.1 - 1 VSD
1 VSD = 0.08 cm
so length of vernier scale is $5\times 0.08=0.4cm$