http://www.webassign.net/mi3/20-072-charging_2_bulb_circuits.jpg In the circuits

Question

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In the circuits shown in the diagrams above, an uncharged capacitor is connected in series with two batteries and either one lightbulb (circuit 1) or two lightbulbs identical to the first bulb(circuit 2). In circuit 1, the lightbulb stays lit for 25 seconds. The following questions refer to these circuits. You should draw diagrams representing the fields and charges in each circuit at the times mentioned, in order to answer the questions.

Question 1:

One microsecond (1e-6 s) after connecting both circuits, which of the following are true? Check all that apply:

The current in circuit 1 is larger than the current in circuit 2

.At the location of the x in circuit 1, electrons flow to the left

At the location of the x in circuit 1, the electric field due to charges on the surface of the wires and batteries points to the right.

In circuit 1 the potential difference across the capacitor plates is equal to the emf of the batteries.

The net electric field at the location of the x in circuit 1 is larger than the net electric field at the location of the x in circuit 2.

At the location of the x in circuit 2, electrons flow to the right.

Question 2:

Two seconds after connecting both circuits, which of the following are true? Check all that apply:

There is more charge on the plates of capacitor 1 than there is on the plates of capacitor 2.

At the location of the x in circuit 2 the net electric field points to the right.

There is negative charge on the left plate of the capacitor in circuit 2.

There is negative charge on the right plate of the capacitor in circuit 1.

At the location of the x in circuit 1 the fringe field of the capacitor points to the left.

At the location of the x in circuit 2 the fringe field of the capacitor point to the right.

Thanks in advance :D

Explanation / Answer

When the second light bulb is inserted into the circuit, the total resistance of the loop increases
(series resistances add), so the current flowing decreases. If the second bulb is identical, the current dropsm to one-half its previous value. Since the current through bulb #1 is now
significantly less than its previous value, the power dissipated by bulb #1 ( P = I^ 2 R ) is now much less than it was

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