Question

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



For the two students, their Ammeter and Voltmeter readings will be minimum when the contact J is in the position:

(1) (a) in both the set ups
(2) (d) in both the set ups
(3) (d) in set up (A) and (a) in set up (B)
(4) (a) in set up (A) and (d) in set up (B)

Answer 1

Ammeter and voltmeter readings will be minimum if the current in the circuit is minimum.

In circuit A, the contact 'J' should be connected at point 'a', so that circuit gets the least power supply which will minimize the current flow in the circuit. In circuit B, the contact 'J' should be connected at point 'd', so that the circuit can have the highest resistance which will minimize the current flow in the circuit.

Hence, the correct answer is option 4.