Download Sci 9 Review Worksheet 9.1 Series and Parallel Circuits With Answers

Science 9 Review Questions 9.1
P306-319
1. What do we call a circuit that has only one path?
A series circuit
2. What happens to the current in a series circuit when a switch is opened?
The current stops everywhere in the circuit
3. How does the total voltage lost on all loads compare to the total voltage supplied by the battery?
The voltage lost on all loads is equal to the voltage supplied by the battery
4. Why is the current at any two locations in a series circuit always the same?
Since there is only 1 path, current (electron flow) can only be of one value. If current were to speed up in
one place, this would be instantly transmitted throughout all the electrons which would all flow at the new
rate.
5. If a resistor is added in series to an existing resistor, what happens to the total resistance?
The total resistance goes up and would be equal to the sum of the resistor’s resistances.
6. What is the name given to a circuit that contains more than one pathway?
A parallel circuit.
7. Two loads are connected in parallel. Compare the voltage across each load.
The voltages of each load would be identical to each other.
8. Two loads are connected in parallel. Must the current through one load equal the current through
the other load?
No. The current can be different in each of the parallel branches.
9. What name is given to a location in a circuit where the circuit branches into more pathways or
where pathways rejoin?
A junction point
10. How does current entering a junction point compare to current leaving that same junction point?
The current entering the junction point will be equal to the current leaving the junction point.
11. If you add a resistor in parallel to an existing resistor, what happens to the total resistance in the
circuit?
The total resistance becomes less.
12. How is a parallel circuit different from a series circuit?
A parallel circuit has two or more paths while a series circuit has just one path.
13. In a series circuit, how does the voltage supplied by the battery compare to the voltages on each
load?
In a series circuit, the voltage supplied is equal to the sum of the voltage losses of all the loads. In a
parallel circuit the voltage supplied is equal to the voltage loss of each load.
14. What happens to the total resistance of a series circuit when another resistor is added in series?
The total resistance becomes greater with each resistor added in series (It is the sum of all the loads’
resistances).
Science 9 Review Questions 9.1
P306-319
15. What happens to the total resistance of a parallel circuit when another resistor is added in parallel?
In parallel circuits, the total resistance lessens with each resistor added in parallel.
16. Two resistors are connected in parallel to a battery. In comparison, what must be the voltage across
each of these two resistors?
In parallel, the voltage loss of each of the resistors is the same as the voltage supplied.
17. Is the current in one branch of a parallel circuit more than, less than, or equal to the total current
entering the junction point of the circuit?
The current in one parallel branch is always less than the total current entering the junction point.
18. The battery in the following circuit is 9.0 V. In this circuit, find :
a. The current through resistor 2
The current through resistor 2 is 2.0 A
b. The voltage across resistor 2
The voltage across resistor 2 is 6.0 V because 3 V (voltage drop) + 6 V (voltage drop) = 9 V (the voltage
rise)
Science 9 Review Questions 9.1
P306-319
19. For the following circuit, find:
a. The current through resistor 2
The current through resistor 2 is 2.0 A because 1A + 2 A = 3 A (The total outside current)
b. The voltage across resistor 2
The voltage across resistor 2 is 9.0 V because in parallel the voltage supplied by the power source is equal
to the voltage loss in each parallel branch.
20. You are given the following circuit. A second resistor is now added in series with resistor 1.
a. Draw the new circuit diagram.
b. Comparing your new circuit to the original, describe the changes in
i. Total resistance
The total resistance is greater than before.
Science 9 Review Questions 9.1
P306-319
ii. Current leaving the cell
The current leaving the cell would be less.
iii. Voltage across resistor 1
The voltage across resistor 1 would be less since the new resistor in series is using up
some of the voltage. (The sum of the voltages of the loads now would be equal to the
voltage used by the resistor before adding the new resistor in series.)
21. You are given the following circuit. A second resistor is now added in parallel with resistor 1.
a. Draw the new circuit diagram.
b. Comparing your new circuit to the original, describe the changes in
i. Total resistance
The total resistance would be less now.
ii. Current leaving the cell
The current leaving the cell now would be more because the total resistance is less.
iii. Voltage across resistor 1
The voltage across resistor 1 would be the same as before since every parallel branch
has the same voltage loss.