Question

What is the relation between the pitch and the least count?

Answer 1

Hint Pitch is the smallest measurement on the main scale while the least count is the smallest measurement an instrument can measure accurately. These values are not constant and may change from instrument to instrument.

Complete Step by step solution
The general relation between pitch and least count is given by
$Leas{t^{}}Count = \dfrac{{pitch}}{{tota{l^{}} numbe {r^{}}o{f^{}} division {s^{}}o{n^{}} circula {r^{}} scale}}$
Where,
Pitch is often defined as the smallest reading that can be taken from the main scale.
Least count is the smallest measurement one can do with an instrument.

Additional information Be careful when you numerically calculate pitch or least count of any measuring instrument because the formula or the way of calculating may vary from instrument to instrument. So, rather than remembering the formulae for every measuring instrument separately, it is more important to understand the concept of measurement using that specific measuring instrument. Then, least count can be easily calculated. For example, least count of a $15cm$ scale and least count of a Vernier calliper or screw gauge conceptually means the same thing. But the way you can calculate it is very different. For a simple instrument like length scale that you use in day to day activities, we can observe that pitch and least count is the same as there is only the main scale. Unlike Vernier callipers which have the main scale and a Vernier scale or screw gauge which has the main scale and the circular scale.

Note It is important to be careful while handling the general formulae for a specific instrument. Every instrument has its own way of measurement. So they may not change in the same way for every measurement tool.