- In a vernier calipers, there are 10 divisions on the vernier scale and 1 cm on the main scale is divided in 10 parts. While measuring a length, the zero of the vernier lies just ahead of 1.8 cm mark and 4th division of vernier coincides with a main scale division. The value of length is

- 1.804 cm
- 1.840 cm
- 1.800 cm
- None of these

Ans. As we know that the measurement taken by a vernier calipers

= reading on main scale just before zero mark of vernier scale

+ (number of divisions of vernier scale coinciding with any main scale division

x least count of the vernier calipers)

Moreover, we know that the least count of any vernier calipers

= the value of smallest division of main scale / number of divisions of vernier scale

= (1 cm/10) / 10 (As per given information)

= 0.1 cm/10

= 0.01 cm

Now, the measurement taken by the vernier calipers

= 1.8 cm + (4 x 0.01 cm) (As per given information)

= 1.8 cm + 0.04 cm

= 1.84 cm

Therefore, **option 2** that is 1.840 cm is correct.