Question

The diagram shown is a section of vernier caliper. Find the least count of the instrument and also the thickness of the metal sheet ?
(A). 0.01 cm, 4.38 cm
(B). 0.02 cm, 5 cm
(C). 0.01 cm, 4.35 cm
(D). None of these

Answer 1

First, find the least count of the vernier scale. Then from the given diagram in the question find the main scale reading of the vernier caliper. Then find the vernier scale reading from the question. Multiply the vernier scale reading with Least count. Add the vernier scale reading and main scale reading to get the final answer.

Complete step-by-step answer:
The Least count of the Vernier scale is,
LC=1MSD−1VSD

Here 10VSD = 9MSD
1VSD=(9/10)MSD

Thus,

LC=(1−9/10)1MSD
That is,

=1/10×0.1cm

=0.01cm (as 1MSR=0.1cm from diagram)

From the given diagram,
We see the main scale reading as,

MSR=4.3cm

And the vernier scale reading as,
VSR=8 (because division 8 coincide with main scale )
Final reading or thickness of the metal sheet is

=MSR+(VSR×LC)=4.3+(8×0.01)=4.38cm
Therefore option A is the correct option.

Additional Information:
Vernier caliper is a measuring device that consists of a main scale as the fixed jaw and the Vernier scale as the moving jaw.
Main scale reading is less accurate as compared to Vernier scale reading.
Least count is the lowest possible amount that can be calculated on that scale.

Note: The main scale reading and the Vernier scale reading are different. We get the total reading of the scale by adding main scale reading and Vernier scale reading together. In the vernier scale we only have to see the division with which the main scale is coinciding then multiply it with least count to find the original value.