Download 5a) Characteristics of a series circuit:

Review Questions - Answers
p. 328-329 # 5 – 11, 13a, 14a, 15 – 16
5 a) Characteristics of a series circuit:
 Amount of current is the same at all points in the circuit
 Amount of current decreases as more loads are added (because there is more resistance)
 The voltage gained by electrons at the source is shared between the loads.
b) Characteristics of a parallel circuit:
 The current leaving the source is split between the different paths
 Amount of current leaving the source increases as more loads are added (because there is less
resistance as more pathways are opened up).
 The voltage gained by electrons at the source is the same as the voltage dropped across each
branch circuit.
6. a) Electrons release most of their energy at the load.
b) A tiny bit of energy is lost in the wires, because the wires have a small amount of resistance.
7. a) When a short circuit occurs, there is no load and so the resistance is very low. This causes large
amounts of current to flow through the circuit.
b) A short circuit can be dangerous because the large amounts of current cause the wire to heat up a lot.
This can result in a fire.
8. When one bulb burns out in a series circuit, then there is a break in the circuit and the other bulbs will all
go out.
9. Series circuits with more than three loads are not very common because if one of the loads stops working,
then they all stop working. Also, as more loads are added in series, the voltage drop across each load
gets smaller and smaller, so the loads wouldn’t work too well.
10. a) all bulbs will glow (complete circuit to all 6 bulbs)
b) nothing will glow (there’s a break in the circuit)
c) 1, 2, 4, and 6 will glow (complete circuit to these four bulbs)
d) Replacing bulb 6 with a copper wire will result in a short circuit in that branch of the parallel circuit.
The electrons will take that easy path rather than going through bulbs 3, 4, and 5, so these three
bulbs will be out (note: this is a bit of a tricky bonus-type question!!!)
11. a) V = I x R = 38 V
b) V = 120 V
c) V = 18 V
13 a) When five 1.8 V cells are connected in series, the electrons will pass through all five cells, gaining 1.8
V through each cell. In total, they will gain 5 x 1.8 V = 9 V
9V
b) The lowest voltage would be if the five cells were connected in parallel. Each electrons would just
go through one cell at a time, picking up 1.8 V.
14. When three 1.3 V cells are connected in parallel, each electron will just go down one path, through ONE
CELL, and pick up 1.3 V. Because the three cells are sharing the work, they will last longer.
1.3V
15. a) Electric current is a measure of the rate of flow of the electrons. To measure current, the ammeter
should be connected in series with the bulb. This way, all the electrons passing through the bulb will
also pass through the ammeter.
b) When you measure the voltage of a battery, you are measuring the amount of energy (volts) that is
gained by the electrons as the electrons move through the battery. To make this measurement, the
voltmeter must be connected across the positive and negative terminals of the battery. It is connected
in parallel.
16. Sorry this diagram is so poor… I need to find a better and quicker way to do this on the computer!!!
Your diagrams on your test should be a bit neater than this please!
18. Four household loads and the form of energy each load produces are:
 radio – converts electrical energy to sound energy
 kettle – converts electrical energy to heat energy
 TV – converts electrical energy into light and sound energy
 Coffee grinder – converts electrical energy into mechanical energy.