Measurement of Length

In a screw gauge, the zero of main scale coincides with fifth division of circular scale in figure (i). The circular divisions of screw gauge are $50.$ It moves $0.5 \mathrm{mm}$ on main scale in one rotation. The diameter of the ball in figure (ii) is:

If $n^{th}$ division of main scale coincides with $(n+1{)}^{th}$ divisions of vernier scale. Given one main scale division is equal to $\text{'}a\text{'}$ units. Find the least count of the vernier.

Consider the Vernier caliper as shown, the instrument has no zero error. The length of the rod (in $\mathrm{mm}$) shown is $\alpha$, if $1 MSD=1 \mathrm{mm}$. Use $7 MSD=8 VSD$. Write the value of $2\alpha$.

The distance advanced by screw of a screw gauge is $2 \mathrm{m}\mathrm{m}$ in four rotation. Its cap is divided into $50$ division. There is no zero error. If the screw reads $3$ divisions on the main scale and $32$ divisions on the cap, then the diameter of the wire is (in $\mathrm{\mu m}$)-

Assertion: Parallax method is used for measuring distances of nearby stars only.
Reason: With increase of distance of star, parallactic angle becomes too small to be measured accurately.

The distance advanced by screw of a screw gauge is $2 \mathrm{m}\mathrm{m}$ in four rotation. Its cap is divided into $50$ division. There is no zero error. If the screw reads $3$ divisions on the main scale and $32$ divisions on the cap, then the diameter of the wire is (in $\mathrm{mm}$)-

What is Vernier Caliper?

Which one of the following instruments is not used for the measurement of length?

The method used by astronomers to calculate how far the star is parallax.

The method used by astronomers to calculate how far the star is _____

Parallax method is based on which of the following principle?

Parallax method is based on which of the following principle?

One Angstrom is equal to:

One angstrom $\left(\mathrm{\AA }\right)$ is equivalent to ${10}^{-10 }\mathrm{m}$.

One angstrom $\left(\mathrm{\AA }\right)$ is equivalent to ${10}^k \mathrm{m}$. The value of $k$ is _____.

One Angstrom is equal to:

What does a fermi measure?

$1$ fermi equal to ${10}^{-15}$ meter?

$1$ fermi equal to ${10}^k \mathrm{m}$. The value of $k$ is _____.

$1$ fermi is equal to