Physics GRE GR 1777

4. Electrodynamics

Solution) Net resistance in a parallel circuit is

Then, total resistance in circuit is

.

By the Ohm’s law, , the total current is ,

.

In a parallel circuit, the current is divided. The ratio of the individual current is the inverse ratio as individual resistance, so

.

Therefore, the current through the resistor is 4A.

The answer is (B).