Question

In an experiment to find the equivalent resistance of two resistors connected is series, a student used the circuit shown:
This circuit will give :



(1) correct reading for voltage V but incorrect reading for current I
(2) correct reading for current I but incorrect reading for voltage V
(3) correct reading for both voltage V and current I
(4) Incorrect readings for both current I and voltage V

Answer 1

An ammeter is a low impedance device and a voltmeter is a high impedance device. In the given circuit the voltmeter is connected in parallel with the ammeter, so the maximum current will pass through the ammeter, that's why the ammeter will give the true reading. The voltmeter is not connected in parallel with the resistors, hence it will not show the actual voltage drop in the circuit, so it will show the incorrect reading.

Hence, the correct answer is option 2.