Question

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

Answer 1

This is called the zero error of the scale of ammeter or voltmeter. If there is a zero error, then
this error is subtracted from the value that is depicted when the circuit is closed, otherwise,
the accurate current or potential difference will not be recorded.