Question

To study the dependence of current (I) on the potential difference (V) across a resistor R, two students used the two setups shown in Figures A and B respectively. They kept the contact point J in four different positions, marked (a), (b), (c) and (d) in the two figures.



For the two students, the ammeter and voltmeter readings will be maximum when the contact J is in the position:
(1) (d) in both the setups
(2) (a) in both the setups
(3) (d) in setup A and (a) in setup B
(4) (a) in setup A and (d) in setup B

Answer 1

The ammeter and voltmeter readings would be maximum when the current in the circuit would be maximum.

In set up A, contact 'J' should be connected to point 'd' as it will give the maximum value of applied voltage, hence the maximum current in the circuit. In set up B, the contact 'J' should be at the point 'a', as it would minimize the net resistance of the circuit and due to that current flow will be maximum.

Hence, the correct answer is option 3.