Question

The least count of a vernier calliper is 0.01 cm and its zero error is – 0.03 cm. While measuring the length of a rod, the main scale reading is 4.6 cm and 8^th division on vernier scale is in line with a marking on the main scale. Calculate the length of the rod.

• A. 4.7 cm
• B. 4.6 cm
• C. 0.03 cm
• D. 4.3 cm

Answer 1

The correct option is A

4.7 cm

Least Count = 0.01 cm
Zero Error = - 0.03 cm
Main Scale Reading = 4.6 cm
Number of vernier division coinciding with the main scale division = 8 i.e., p = 8
Length of the rod = Observed Reading - Zero Error
= [Main Scale Reading + (Vernier division coinciding $\times$ L.C.) - Zero Error
$=\left[\right(4.6cm)+(8\times 0.01cm\left)\right]-(-0.03cm)=(4.6cm+0.08cm)-(-0.03cm)=4.68cm+0.02cm=4.7cm$