Question

The diameter of a cylinder is measured using vernier calipers with no zero error. It is found that the zero of the vernier scale lies between 5.10 cm and 5.15 cm of the main scale. The vernier scale has 50 divisions equivalent to 2.45 cm. The ${24}^{th}$ division of the vernier scale exactly coincides with one of the main scale divisions. The diameter of the cylinder is :

• A. 5.112 cm
• B. 5.124 cm
• C. 5.136 cm
• D. 5.148 cm

Answer 1

Answer: (B)

5.124 cm

Main scale can measure $5.10$ and $5.15$
$\therefore$ Main scale division (s) $=0.05cm$

Also, vernier scale division (v) $=\frac{2.45}{50}=\frac{4.9}{100}=0.049cm/div$

Thus, least count $=0.05-0.049=0.001cm$
Diameter $=5.10+24\times 0.001$
$=5.124cm$