Question

Explain the meaning of the term ‘least count of an instrument’ with the help of a suitable example.

Answer 1

Hint: Least count of an instrument means instrument having less error. Least count means smallest division. It is one type of error. Least count is always related to instrument. Least count is meant to check how well our practice is going.

Complete step-by-step answer:
All the readings or measured values are good enough only up to this least count.
Least count error is the error which is concerned with the resolution of the instrument. Now let's understand this concept with the help of an example, we all know what vernier calliper is. You must have used it in practical. A vernier calliper has a least count of 0.01 cm. A spherometer may have a least count of 0.0001cm, it means that different measuring instruments have different-different least count.

Least count error belongs to the category of random errors, but it has limited size. It occurs with both systematic and random errors. If we will use a meter scale to measure the length. Then it may have graduations at 1 ml division scale, spacing or interval.

Using instruments of higher precision, improving sensitivity and also improving experimental techniques etc. We can reduce a least count error by using a vernier calliper having good precision and also we can reduce the error by repeating the observation several times and taking the arithmetic mean of all observations. The calculated value which is known as mean value will be very close to the true value of the measured quantity.

Note: Error is nothing but uncertainty. Every calculated quantity which is based on measure value will have error. Accuracy and precision are two different things and are very important while you are performing particles. Always calculate error once you are done with readings and calculation.