Question

A student measures the diameter of a metal circular disc using vernier calipers with least count $0.01cm$. If zero division on the vernier scale is in between the 4.5 cm and 4.6 cm on main scale and 6 division on vernier scale coincide with any line of the main scale, the radius of the circular disc is

• A. $4.56cm$
• B. $2.33cm$
• C. $4.66cm$
• D. $2.28cm$

Answer 1

Answer: (D)

$2.28cm$

Here least count, $LC=0.01cm$
The main scale reading (MSR) of the calipers is always left side of the zero of vernier scale. So less value will be the main scale reading. Thus, $MSR=4.5cm$
Here, vernier scale reading , $VSR=6$
Thus, total reading or diameter , $d=MSR+(VSR\times LC)=4.5+(6\times 0.01)=4.56cm$
The radius will be $r=d/2=2.28cm$