The least count of a vernier caliper is 0.005 cm . It is given that 20 divisions of the vernier scale coincide exactly with 19 divisions of the main scale. The number of main scale divisions present in 1 cm of the main scale is :

Step-by-step solution

Let the length of one main scale division be 1 MSD and the length of one vernier scale division be 1 VSD . Given that 20 VSD = 19 MSD 1 VSD = 19 20 MSD The least count (LC) is given by: LC = 1 MSD - 1 VSD LC = 1 MSD - 19 20 MSD = 1 20 MSD We are given LC = 0.005 cm . 1 20 MSD = 0.005 cm 1 MSD = 20 0.005 cm = 0.1 cm The length of one main scale division is 0.1 cm . Therefore, the number of main scale divisions in 1 cm is: Number of divisions = 1 cm 0.1 cm = 10 Answer: 10