Question

In the experiment on finding the equivalent resistance of two resistors connected in series, three students connected the ammeter in their circuits in the three ways X, Y and Z shown here.



Assuming their ammeters to be ideal, the ammeters have been correctly connected in
(1) cases X and Y only
(2) cases Y and Z only
(3) cases Z and X only
(4) all the three cases

Answer 1

An ideal ammeter has negligible or zero resistance, hence it measures the actual current flowing in the circuit. It can be connected anywhere in the circuit in series with the battery and the resistance of the circuit given that current should enter into it from the positive terminal and leave from the negative terminal. The ammeter is not connected with appropriate polarity in circuit Z. In circuit Z, the polarity of the ammeter is wrong. So in circuit X and Y, the ammeters have been correctly connected.

Hence, the correct answer is option 1.