LEAST COUNT:

Least count of an instrument in physics is the smallest measurement that can be accurately read or estimated with that instrument.It represents the instrument’s precision increment that can be measured.

                                                                                    OR

Least count of any instrument is the littlest division that can be estimated utilizing the instrument.

Here’s how the least count works for some common instruments.

Least count of a voltmeter:

Least count is the smallest scale division marked on the meter.If the meter has a scale that reads up to 10 volts with 50 divisions, then the least count is 0.2 volt.

                                            Voltmeter Reading = Pointer division X least count

                                                                                = 30 ^th division X 0.2 V = 6V

LEAST COUNT OF AMMETER 

Least count of micro-ammeter:

Least count is the smallest scale division marked on the meter.If the meter has a scale that reads up to 100 microampere with 50 divisions, then the least count of the microammeter is 4 micro ampere.

                                           Let us assume the pointer pointing 10 ^th division

                                            Microammeter Reading = Pointer division X least count

                                         = 10 ^th division X 4 microampere = 40 microampere

Least count of  a screw gauge

A screw gauge, sometimes referred to as a micrometer, is a device used to measure small dimensions with high precision. It consists of a calibrated screw that moves to measure the distance between its spindle and anvil, enabling the user to determine the thickness, diameter, or width of an object.

A screw gauge is a mechanical tool used to accurately measure the diameter or thickness of tiny items. It works on the basis of a screw mechanism, in which an object is measured by a spindle moving in tiny increments.

Screw gauge -Image

Pitch of a screw gauge

Screwgauge – Least count

LEAST COUNT OF A VERNIER CALIPER 

Vernier Caliper – Image

LEAST COUNT OF A GRADUATED SCALE:

LEAST COUNT OF A MEASURING BEAKER 

Importance of least count:

• Instruments with a smaller least count can measure more precisely.
• The least count helps in estimating the measurement uncertainty.
• Understanding the least count is crucial for making precise measurements and evaluating the accuracy of the data obtained from experiments.