Q.

A Vernier callipers has 20 divisions on the Vernier scale, which coincides with 19th division on the main scale. The least count of the instrument is 0.1 mm. One main scale division is equal to _______ mm.           [2024]

1 1  
2 5  
3 2  
4 0.5  

Ans.

(3)        

             20 VSD=19 VSD1 VSD=1920 MSD

               L.C.=1 MSD-1 VSD=1 MSD-1920 MSD

               0.1 mm=120 MSD

               Hence, 1 MSD=2mm