In an instrument, there are 25 divisions on the vernier scale which coincide with 24th division of the main scale. 1 cm on main scale is divided in 20 equal parts. The least count of the instrument is

 

•  In an instrument, there are 25 divisions on the vernier scale which coincide with 24th division of the main scale. 1 cm on main scale is divided in 20 equal parts. The least count of the instrument is 

1. 0.002 cm
2. 0.05 cm
3. 0.001 cm
4. 0.02 cm 

    Ans. As we know that the least count of a vernier calipers is 

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

            = (1 cm / 20) / 25

            = (10 mm / 20) / 25

            = 0.5 mm / 25

            = 0.02 mm

            = 0.002 cm

            Therefore, option 1 that is  0.002 cm is correct.