Vernier Caliper and Screw Gauge

Find the thickness (in $\mathrm{mm}$) of a five rupee coin with the screw gauge, if the pitch scale reading is $1 \mathrm{mm}$ and its head scale coincidence is $68$. Give the answer in up to two decimal points. (Least count = $0.01 \mathrm{mm}$)

The main scale reading while measuring the thickness of a rubber ball using Vernier Caliper is $7 \mathrm{cm}$ and the Vernier scale coincidence is $6$. Find the radius (in $\mathrm{cm}$) of the ball up to two decimal points.(Least count = $0.01 \mathrm{cm}$)

How will you find the thickness of a one rupee coin?

Explain a method to find the thickness of a hollow tea cup.

How will you measure the least count of vernier caliper?

Define least count of any device.

Thickness of a small ball can accurately measure by _____.

(Choose from the following: vernier calipers/ metre scale)