Question

What would you suggest to a student if while performing an experiment he finds that the pointer/needle of the ammeter and voltmeter do not coincide with the zero marks on the scales when the circuit is open? No extra ammeter/voltmeter is available in the laboratory.

Answer 1

Experiment:

Every experiment has some error associated with it.

In this case, we have an error with the most minor count which is a systematic error.

Step 1:

So, before you begin the experiment, you must determine the most minor count for both meters.

Step 2:

When the needle of the voltmeter/ammeter does not coincide with the zero mark in the open-circuit state then there is a zero error. Depending upon the type of zero error, the zero error value is subtracted or added to the observed value to obtain the final result.

Step 3:

The experiment is then carried out, and the value obtained as the final reading is recorded.

Step 4:

That meter could be connected to the circuit following calculating the value through an open circuit that would be treated as the starting reading or quantity for that measurement.

Hence, this same final reading or value would be the measurements acquired after connecting the circuit.