Question

Lowest limit of measurement using any measuring instrument is known as:
A. Highest scale
B. Least count
C. Limit count
D. All of these

Answer 1

Now first let us see what measuring instruments are-
Measuring instruments are measuring machines that transform an indicator or information into a calculated quantity or a similar quantity.
Measuring instruments may either directly mean the value of the quantity measured or merely mean its equality with a known calculation of the same quantity.
Measuring range is the set of determined quantity values for which the quantity and the error obtained from a single calculation does not surpass the overall allowable error under standard conditions of usage.

Complete step by step solution:
Now let us look at option A what highest scale is-
Highest scale is an interval scale with the additional property that the absence of the quantity being measured is implied by its zero position. The highest level of measurement is a ratio.

The option B is least count.
Now let us have a look at what least count is-
The lowest value that the measuring instrument can measure is considered as the least count. The lowest count error is the error correlated with the instrument’s resolution. The formula for the Vernier Calliper least count is determined by dividing the smallest reading of the main scale with the total number of Vernier scale divisions. Similarly least count for screw gauge, rain gauge etc. can also be calculated.

The option C is limit count.
Limit count- The uncertainty of the scale provides an arbitrary limit to the accuracy of the measurement, i.e. the number of values within which the “true value” of the measurement lies cannot be less than the uncertainty of the scale.
So, from the above discussions it can be concluded that the lowest limit of measurement is least count.

Hence, option B is correct.

Note: We should keep in mind that there may be errors while measuring the lowest value of an instrument. This error is known as the least count error. It can be minimized by using instruments of higher precision and by repeating the observations. We shall not get the exact value, but by reducing the errors the observed value will be close to the true value.