Q30P The capacitor in Figure 19.67 is... [FREE SOLUTION]

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Chapter 19: Q30P (page 797)

The capacitor in Figure 19.67 is initially uncharged, then the circuit is connected. Which graph in Figure 19.66 best describes the current through the bulb as a function of time?

Short Answer

Expert verified

Figure (d) best depicts the current in the circuit.

Step by step solution

Given data

An uncharged capacitor is connected to a bulb and two batteries in series.

Charging of a capacitor

When an uncharged capacitor is connected to a battery, positive charges from the positive end of the battery flow to one plate of the capacitor and start accumulating there and negative charges from the negative end of the battery move to the other plate of the capacitor and start accumulating there.

Determination of the graph of the current in the circuit

As charges accumulate on the plates of the capacitor, a fringe field is developed in the circuit which opposes the field from the battery. As charge concentration increases on the plates, so does the fringe field. The net field in the circuit decreases which decreases the current. This continues until the fringe field completely cancels out the field from the battery and current in the circuit is zero. This is best depicted by figure (d).