The vernier of a circular scale is divided into 30 divisions, which coincides with 29 main scale divisions. If each main scale division is (1/2)°, the least count of the instrument in minutes is:
Physics · Mixed Chapter
JEE Mains

Question

The vernier of a circular scale is divided into 30 divisions, which coincides with 29 main scale divisions. If each main scale division is (1/2)°, the least count of the instrument in minutes is:

G1 Physics · Accepted Answer

Step 1: Thirty vernier divisions coincide with 29 main-scale divisions, so 1 VSD=(29/30) MSD. Step 2: Least count = 1 MSD−1 VSD = (1/30) MSD. Step 3: Since 1 MSD=0.5°=30 arcminutes, least count=30/30=1 arcminute. Hence answer 1.