Ohm S Law

The current in a circuit can be found using Ohm's law, which is given by: where: - is the emf of the cell, - is the total resistance of the circuit. Let's analyze the current in each case. Case (a): Without any external resistance In this case, the circuit consists of only the internal resistance of the cell. Therefore, the total resistance in the circuit is: Thus, the current is: Case (b): With resistance only In this case, the total resistance is the sum of the internal resistance and : Thus, the current is: Case (c): With and in series combination In this case, the total resistance is: Thus, the current is: Case (d): With and in parallel combination In this case, the total resistance is: Thus, the current is:
We can now compare the values of , , , and . Since the total resistance in case (a) is the smallest, the current will be highest in that case. For the other cases, the total resistance increases, and thus the current decreases in the following order: Thus, the currents measured in the four cases in ascending order are , which corresponds to option (A).