Question

The vernier scale of a travelling microscope has 50 divisions which coincide with 49 main scale divisions. If each main scale division is 0.5 mm, then the least count of the microscope is

• A. 0.01 cm
• B. 0.5 mm
• C. 0.01 mm
• D. 0.5 cm

Answer 1

Answer: (C)

0.01 mm

Answer 2

1 MSD = $0.5$ mm

50 VSD = 49 MSD

1 VSD = $\frac{49}{50}MSD$

Least count = 1 MSD 1 VSD

$= 1MSD - \frac{49}{50}MSD = \frac{1}{50}MSD = \frac{1}{50} \times 0.5mm = 0.01mm$