Question

The vernier scale of a callipers has 50 divisions
which coincide with 49 main scale divisions. If
each main scale division is of 0.5 mm, then the
minimum inaccuracy in the measurement by
callipers is
(1) 0.02 cm
(2) 0.02 mm
(3) 0.01 mm
(4) 0.01 cm​

Answer 1

answer : option (3) 0.01mm

explanation : a/c to question,

50 Vernier scale divisions = 49 main scale divisions

or, 1 V.S.D = 49/50 M.S.D ....(1)

[ given, Vernier scale division = V.S.D and main scale division = M.S.D ]

least count = 1M.S.D - 1V.S.D

from equation (1),

= 1 M.S.D - 49/50 M.S.D

= 1/50 M.S.D

each main scale division = 0.5mm

so, least count = 1/50 × 0.5 mm

= 0.5/50 mm

= 0.01 mm

least count is also known as minimum inaccuracy in the measurement by calliper. so, answer should be 0.01mm