Question

Why is the use of zero error necessary in measuring instruments?

Answer 1

1. Zero error- It is an error that occurs in an instrument when the instrument gives an accurate reading that is zero at that time.
2. Zero error has to be considered in the calculation for an instrument to get accurate results.
3. Example - In a vernier caliper, zero error is calculated by setting the main scale in such a way that it does not coincide with the vernier scale. Then the vernier caliper is said to have a zero error. Zero error is the distance between the vernier scale and the main scale. It can be positive or negative.

In this diagram, the coinciding division is the 6th one,$n=6$

Zero error of vernier calliper=Least count $\times$$n$

The least count of any instrument is the least unit it can measure, here it is $\frac{1mainscaledivision}{divisionsonmainscale}=\frac{1}{10}cm=0.1mm$

Therefore the zero error here is $n\times leastcount=6\times 0.1=0.6mm$

Therefore, it is necessary to have zero error in measuring instruments.