Close Switch 2 J 800 3 4 2 Graded 2: State whether the light bulbs below are a) in series b) in parallel or c) neither. Remember that if resistances are in series, the current through each must be the same. If resistances are in parallel, the voltage across each is the same since their ends are connected together. Bulbs 1 and 2: Bulbs 1 and 3: Bulbs 2 and 3: Branch with bulbs 1 and 2 and Bulb 3: Bulbs 1 and 4: Bulbs 3 and 4:

Consider the circuit below. The capacitor has a capacitance of 10 mF. The switch is closed and after a long time the capacitor is fully charged, (a) What is the current through each resistor a long time after the switch is closed? (b) What is the voltage across each resistor a long rime after the switch is closed? (c) What is the voltage across the capacitor a long time after the switch is closed? (d) What is the charge on the capacitor a long time after the switch is closed? (e) The switch is then opened. The capacitor discharges through the resistors. How long from the time before the current drops to one fifth of the initial value?

Consider the circuit below, (a) What is the initial current through resistor R2? when the switch is closed? (b) What is die current through resistor R2 when the capacitor is fully charged, long after die switch is closed? (c) What happens if the switch is opened after it has been closed for some rime? (d) If the switch has been closed for a time period long enough for the capacitor to become fully charged, and then the switch is opened, how long before the current through resistor R1 reaches half of its initial value?

Is a circuit breaker wired (a) in series with the device it is protecting, (b) in parallel, or (c) neither in series or in parallel, or (d) is it impossible to tell?

The IR drop across a resistor means that there is a change in potential or voltage across the resistor. Is there any change in current as it passes through a resistor? Explain.

A student claims that the second of two lightbulbs in series is less bright than the first because the first lightbulb uses up some of the current. How would you respond to this statement?

What would be the maximum cost of a CFL such that the total cost (investment plus operating) would be the same for both CFL and incandescent 60-W bulbs? Assume the cost of the incandescent bulb is 25 cents and that electricity costs 10 cents/kWh, Calculate the cost for 1000 hours, as in the cost effectiveness of CFL example.

If two different wires having identical cross-sectional areas carry the same current, will the drift velocity be higher or lower in the better conductor? Explain in terms of the equation vd=1nqA by considering how the density of charge carriers n srelates to whether or not a material is a good conductor.

Consider the circuits shown below, (a) What is the current through each resistor in part (a)? (b) What is the current through each resistor in part (b)? (c) What is the power dissipated or consumed by each circuit? (d) What is the power supplied to each circuit?

Consider the circuit in Figure 27.17 and assume the battery has no internal resistance. (i) Just after the switch is closed, what is the current in the battery? (a) 0 (b) /2R (c) 2/R (d) /R (e) impossible to determine (ii) After a very long time, what is the current in the batten? Choose from the same choices. Figure 27.17 (Quick Quiz 27.5) How does the current vary after the switch is closed?