If $x$ vernier scale division is equal to $Y$ main scale division where $1 \mathrm{M}.\mathrm{S}.\mathrm{D}.$ is $1 \mathrm{cm}$, then find L.C.

A student measured the length of a rod and wrote it as $3.5 \mathrm{cm}$. Which instrument did he use to measure it?

Write T for the true statement and F for the false one. Correct the false statement(s).

Estimation is a very accurate method of measurement.

The pitch of a screw gauge is $0.5 \mathrm{mm}$ and its head scale has $50$ divisions. The least count of the screw gauge is:

If ten students are asked to measure the length of a piece of cloth up to a $\mathrm{mm}$, using a metre scale, do you think their answers will be identical? Give reasons.

Measure of two quantities along with the precision of respective measuring instrument is

$A = 2.5 m s^{-1} \pm 0.5 m s^{-1}$

$B = 0.10 s \pm 0.01 s$

The value of AB will be