Download V - Pukekohe High School

Name
Form
Current Thinking
hiko
Light and Energy
Feedback  Feedforward
What result are you going to aim for in your theory test? (Circle below)
A
M
E
Have you done the following steps to help you achieve your goal?
Task
Read through my notes
Completed my homework book
Marked my homework book
Completed the crossword
Completed glossary list
Completed background reading
Completed some practice questions
Asked the teacher at least one question you are
unsure about
Completed minimum of one study technique:
 Concept map
 Brief notes
 Keyword flipcards
 Mix n Match
 Spider Map
 Mnemonics
 Acronyms
Did you achieve your goal? (circle)
YES
NO
Can you set 3 goals for the next topic?
(Including a goal for your bookwork)
1) _________________________________________________________
2) _________________________________________________________
3) _________________________________________________________
Specific Learning Outcomes

By the end of this topic you should be able to
1. Know about electrical charges, conductors and insulators, recognise circuit symbols and
distinguish between series and parallel circuits.
2. Define current / voltage (simple terms) and describe how they are distributed and measured
in series and parallel circuits. Demonstrate how to construct a simple circuit and take
measurements from electrical meters.
3. Understand the ideas of power and resistance.
4. Understand the properties of magnets and how electromagnets work.
Glossary of Terms
Static electricity_______________________________________________________________________
Current electricity_____________________________________________________________________
Conductor____________________________________________________________________________
Insulator_____________________________________________________________________________
Negatively charged_____________________________________________________________________
Positively charged______________________________________________________________________
Circuit_______________________________________________________________________________
Electrons_____________________________________________________________________________
Cells________________________________________________________________________________
Terminal_____________________________________________________________________________
Repel________________________________________________________________________________
Attract_______________________________________________________________________________
Protons______________________________________________________________________________
Series circuit__________________________________________________________________________
Parallel circuit_________________________________________________________________________
Potential energy_______________________________________________________________________
Current______________________________________________________________________________
Energy supplier _______________________________________________________________________
Component __________________________________________________________________________
Ammeter ___________________________________________________________________________
Ampere _____________________________________________________________________________
Direct current _________________________________________________________________________
Alternating current ____________________________________________________________________
Voltage ______________________________________________________________________________
Voltmeter____________________________________________________________________________
Joule ________________________________________________________________________________
Electrical force field ____________________________________________________________________
Fuse ________________________________________________________________________________
Resistance___________________________________________________________________________
Resistor ____________________________________________________________________________
Rheostat ____________________________________________________________________________
Ohm
______________________________________________________________________________
Power ______________________________________________________________________________
Watt
______________________________________________________________________________
Magnetic field ________________________________________________________________________
Compass ____________________________________________________________________________
North pole ___________________________________________________________________________
South pole___________________________________________________________________________
Magnetized __________________________________________________________________________
Unlike poles _________________________________________________________________________
Like poles ____________________________________________________________________________
Electromagnet ________________________________________________________________________
Electric motor ________________________________________________________________________
CT1
Charge
What happens to two charged rods held near each other if they
have: a) the same charge_____________________________________
b) a different charge____________________________________
What charge is left on a material if it has been rubbed and:
a) looses electrons_____________________________________
b) gains electrons______________________________________
Which of the following are conductors and which are insulators?
a) copper_____________________________
b) plastic _____________________________
c) steel _____________________________
d) air
e) wood
_____________________________
____________________________
f) salt water _________________________
Energy Changes
Give an example of a situation where electrical energy is changed into:
a) sound energy ___________________________________________
b) light energy ____________________________________________
c) heat energy _____________________________________________
d) kinetic energy ___________________________________________
CT2
Circuit symbols
Symbol
1 Complete this symbol table.
Component
Function
Light bulb
To measure current in a circuit
Give three rules to be remembered when drawing circuit diagrams.
_____________________________________________________
_____________________________________________________
_____________________________________________________
CT3
1.The diagram shows a simple electrical circuit. Draw a circuit diagram
for this set up.
2. Draw these circuit diagrams:
a) A farmyard torch has 4 cells in series in its case with a bulb and a switch
b)i) A circuit which contains three cells in series with a bulb and a rheostat.
ii) Which component could be used to dim the light of the bulb?_______________________
b) Two lamps are to be placed in parallel branches with a cell, but one is to have a rheostat connected in
series with it so that it may be dimmed, while the other has an ammeter in series with it and a
voltmeter in parallel across it.
c) A circuit containing a battery and two branches with a bulb in each. Add three switches that will
allow you to turn off
a) both bulbs
b) each bulb separately
CT4
Explain in your own words the difference you can see between a series circuit and parallel
circuit
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
What are the advantages of a parallel circuit compared to a series circuit? Use the example of
Xmas tree lights.
___________________________________________________________________________
___________________________________________________________________________
CT5
Current
A
Current is a flow of ___________through a circuit.
An ampere is the correct name for an _________.
An amp has the symbol ___________.
Ammeters must be connected in________________
Complete these diagrams by filling in the unknown ammeter readings.
a) Ammeter A reads 1.4 amp.
A
A1
A2
b) Ammeter A reads one amp.(all of the bulbs are identical)
A1
A2
A3
A
CT 6
Electric current in your home.
a) What can causes an increase in the current in the wiring?
__________________________________________________________
b) What happens to a wire that has too high a current going through it and what might be the result?
__________________________________________________________
c) Draw the circuit symbol for the component that is used to protect your home from an electrical fire due
to overloading of the electrical wiring.
d) Explain how this component protects your home from an “electrical fire”. due to overloading the
electrical circuit?
__________________________________________________________________________________
__________________________________________________________________________________
CT7
Voltage
a) What does “voltage” measure? (explain in your own words)
___________________________________________________
b) One volt is _________________ joule of energy per __________
coulomb of charge.
c) Voltmeters measure voltage. List two things to remember when connecting a voltmeter into a
circuit.____________________________________________________
____________________________________________________
d) Find out the voltage used in the following:
house
V
car
V
toaster
V
battery powered toy
V
electric jug
V
high voltage power line
V
Complete the diagrams, by writing the voltmeter readings onto the diagrams.
The bulb without a voltmeter is
using 8.0V.
Voltmeter V12 reads 4.0V. The bulbs with
voltmeters V12 and V13 are identical
CT8 A trip to town
A group of friends collected their allowance and went into town to spend it. The places they went
are shown on the map. Their journey is shown on the map and also as a circuit diagram.
1.
Use both diagrams to answer the questions below.
a.
How many went bowling?__________________
b.
How many didn’t go bowling? ______________
c.
How many went to the rugby game? ____________
d.
How many went to the Game Zone? ______________
e.
How many went over the bridge? _______________
f.
How much did it cost to play bowls? ________________
g.
How much was each person’s allowance? ________________
h.
How much did the burgers cost? ____________________
i.
How much did the Game Zone cost? ____________________
j.
How much does an ice cream cost? ________________
2. Fill in the missing meter readings on the circuit diagram above.
3. Work out the values of the meters
in the circuit diagram on the right, and write
them on the diagram.
CT9
A test of resistance
1
Kay measured the current through
two types of resistance wire (A and B)
for a range of lengths
These are her results:
Wire A – 1.9A: 30cm
Wire B – 0.3A: 60cm
Wire A – 40cm 1.6A
Wire B – 20cm 1.2A
Wire A - 60cm 1.4A
Wire A - 20cm 2.2A
Wire B - 0.8A
30cm
Wire B – 40cm 0.6cm
2
Complete the table below, putting her results in a sensible order.
What happens to the current in the wire as the length increases?
____________________________________________________________
What happens to the resistance of the wire as the length increases?
____________________________________________________________
____________________________________________________________
Which of the two wires has the greater resistance?
__________________________________________________________
State one factor that should remain constant during the experiment.
____________________________________________________________
Calculate the resistance for wire B 20cm long.
___________________________________________________________
___________________________________________________________
CT10
Power
Complete the table below. (Don’t forget units.)
Appliance
Heater
Laptop Computer
Soldering Iron
CT11
Voltage
240V
Current
Power
3A
14V
42W
2A
25W
MAGNETISM
Use a fridge magnet and find out if the following materials are attracted to a magnet, put the information
into the table, label the columns: Paper clip, hair pin, tack, toothpick, rubber band, straw, paper, fabric,
concrete, 5 different coins, plastic, parts of a car, bicycle or skateboard.
Write a summary on the type of material attracted by a magnet!
CT12
Electromagnets
Ruth and Rowena are investigating electromagnets. They set up their equipment as shown in the
diagram.
1
Draw a circuit diagram of their setup in the space above.
2
How could the two girls measure the strength of the electromagnet they made, using the paper clips
provided?
________________________________________________________________________________
__________________________________________
3
4.
They varied the current flowing in the circuit using the rheostat.
a.
Plot a graph of the number of paper clips attracted versus the current, using the results shown
in the table.
b.
What does this graph show about the strength of the electromagnet as the current increases?
__________________________________________________________
Current
(A)
Number of paper clips
attracted at 5cm
0.4
1
0.8
2
1.2
3
1.6
4
2.0
5
State three factors that Ruth and Rowena kept constant during their investigation
i ___________________________________________ ii _____________________________
__________________________ iii ______________________________________________
5.
List two ways in which the girls could make a stronger electromagnet for a given
current in the coil.
6.
____________________________ ii _________________________________
Give two uses for electromagnets in everyday life.
i _______________________________________ ii ______________________________________
CT13
This is an example of a magnetic field around
a bar magnet
Draw the magnetic field around these magnets.
N
S
N
S
N
S
S
N
Find 6 uses for magnets in your household.
i _____________________________________________
ii _____________________________________________
iii _____________________________________________
iv _____________________________________________
v _____________________________________________
vi _____________________________________________
CT14
Revision Crossword Current Thinking
Across
1. Units of resistance.
6. Device which produces electricity
8. Lets the current travel in one direction only.
9. The build up of electrical charge on an insulator.(6,11)
11. Current which travels in one direction only.
14. Circuit in which there are two or more loops.
15. A component which determines the size of the current.
16. A thin wire which melts if the current is too large.
17. Total amount of energy supplied or used per second.
18. Complete conducting loop.
19. Current carrying coil wrapped around an iron bar.
20. Object that allow electrons to travel through.
21. A variable resistor.
22. Point of attachment for wires to a battery or ammeter.
23. Negatively charged particles which orbit the nucleus.
Down
2. Circuit in which all the components are in a single loop.
3. Units of energy
4. Unit of voltage
5. Used to measure the voltage gain or loss in a circuit.
7. Units of power.
10. Objects that do not allow electrons to travel through.
12. The flow of electrons around a conducting pathway
13. Current which keeps changing direction.
15. Units of current
18. Object with a magnetised needle which is free to rotate.