Q.

The diameter of a sphere is measured using a Vernier calliper whose 9 divisions of main scale are equal to 10 divisions of Vernier scale. The shortest division on the main scale is equal to 1 mm. The main scale reading is 2 cm and second division of Vernier scale coincides with a division on main scale. If mass of the sphere is 8.635 g, the density of the sphere is                      [2024]

1 2.5 g/cm3  
2 1.7 g/cm3  
3 2.0 g/cm3  
4 2.2 g/cm3  

Ans.

(3)       

                 Given: 9 MSD=10 VSD,m=8.635 g

                  LC=1 MSD-VSD

                 LC=1 MSD-910MSD=110MSDLC=0.01 cm

                 Reading of diameter=MSR+LC×VSR

                 =2cm+(0.01)×(2)=2.02 cm

                 Volume of sphere=43π(d2)3=43π(2.022)3=4.32cm3

                 Density=massvolume=8.6354.32=1.998~2.00 g/cm3