Download electricity and energy student notes

Name ______________________
Teacher _______________________
Electricity and Energy Sources CfE
Physics Level 4
Physics Skill
Numeracy Skill
Literacy Skill
Course Content
CIRCUIT THEORY
Through investigation, I understand the relationship between current, voltage and
resistance. I can apply this knowledge to solve practical problems. SCN 4-09 a
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I can use the software YENKA to build a simple series circuit.
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I can draw the circuit symbols for: cell, battery, power supply, wire, resistor, variable resistor,
fuse, light emitting diode (LED), voltmeter, ammeter and ohmmeter.
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I can build a series circuit from a circuit diagram
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I can correctly attach an ammeter and a voltmeter in a circuit
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I can investigate the effect that increasing the voltage of a power supply has on the current in
a circuit
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I can use spreadsheets and graphs to describe a direct proportion relationship
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I can convert from mA to A and kV to V
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I can describe the electron as a negative charge carrying particle
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I can use the terms Voltage, Voltmeter and Volts correctly
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I can use the terms Current, Ammeter and Amperes correctly
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I can describe Voltage and Current in terms of Energy, Charge and Time
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I can use the terms Resistance, Ohmeter and Ohms
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I can use Ohm’s Law, V = IR, to solve simple proportional problems, know the meaning of
each symbol and its unit
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I can rearrange a three term equation
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I can describe the effect of a resistor on the current in a circuit.
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I can state the equation and know how to calculate the total resistance of two or more
resistors in series
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I can state the energy change in a resistor.
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I can use voltage and current readings to calculate the resistance or power output of a
component I = V/R and P = IV
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I can state the rule for current in a series circuit.
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I can state the rule for voltage in a series circuit.
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I can state the rule for current in a parallel circuit
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I can state the rule for voltage in a parallel circuit.
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I can state some advantages of using a parallel circuit over a series circuit.
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I can state two common situations where parallel circuits are used
ELECTROMAGNETISM
I can help to design and carry out investigations into the strength of magnets and
electromagnets. From investigations, I can compare the properties, uses and
commercial applications of electromagnets and super magnets.
SCN 4-08a
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I have investigated permanent magnets and can draw the magnetic field lines around a bar
magnet
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I can state that a current carrying wire produces a magnetic field
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I can draw the magnetic field lines around a current carrying wire
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I can describe how an electromagnet is made using a diagram
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I can draw the magnetic field lines around an electromagnet
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I can describe an investigation into the factors affecting the strength of an electromagnet
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I can state the main difference between a commercial magnet and a school electromagnet
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I have investigated the main uses of electromagnets and super magnets in industry
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I have built an electric motor and can name the 4 main parts

I have investigated electromagnetic induction and can describe the criteria for an induced
voltage
SOURCES OF ELECTRICAL ENERGY
By contributing to an investigation on different ways of meeting society’s energy needs,
I can express an informed view on the risks and benefits of different energy sources,
including those produced from plants.
SCN 4-04a
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I can describe the main energy changes in a power station
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I understand the role of the national grid and can explain how electrical energy is transferred
around the country
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I have investigated a type of renewable and non renewable energy resource and understand
the advantages and disadvantages of each

I can state the main problems facing a “sustainable energy society”
Circuit Theory
A simple series circuit can teach us a great deal about the behaviour of electrical energy
Electricity describes the control of electrically charged particles (electrons).
Voltage is the Energy given to a bunch of charge carrying particles. It can be thought of as the “push”
from the power supply.
Current is the amount of charge flowing through a conducting material. It can be though of as the
“flow” of charge.
Ohm's Law connects these two values together and indicates how easily current will flow.
Various experiments can be done to prove
this.
1/ Take a fixed value of resistor and
change the voltage to see how it affects the
current.
A higher voltage gives a larger current.
2/ Keep the supply voltage constant and
use different values of resistor to see how it
affects the current. A larger resistance
gives a smaller current.
These graphs show how electrical current
behaves when voltage and then current is
increased.
The first graph shows that more push gives
more flow.
The resistance of a material describes how
hard it is for charge to flow through it and
the second graph shows that a high
resistance gives a low flow.
Current and Voltage in Series and Parallel
Resistors in series can be added together:
Resistors in parallel need more care:
R1 + R2 + R3 = Rtotal
In general, parallel circuits are used more often than series circuits. This has several advantages:
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A break in the circuit does not cause the entire circuit to fail.
Each component gets the same energy per charge.
More components can be added without breaking the original circuit.
Parallel circuits are used in household wiring, cars and streetlamps etc
Electromagnetism
When a current passes through a wire a
magnetic field can be detected around it. The
direction of the field depends on the direction
of the current. The strength of the magnetic
field depends on the size of the current and the
number of current carrying wires.
Movement from Electricity:
If this electric magnet (electromagnet) is placed next to a secondary magnet then the forces cause
movement to occur. This can be used to create movement from electricity. Several inventions take
advantage of this. For example the electric motor:
Electricity from Movement:
If a magnetic field is placed near a copper wire and wiggled around then a current is induced in the wire.
The current only appears when the magnetic field is changed. A larger magnitude of change will
produce a larger current, and therefore voltage in the wire. This is how electricity is produced in most
power stations. The current is alternating as the magnetic field is always changing. Usually something
is burned to produce steam and spin a magnet.
Getting the wire/magnet to move is the job of a power station. This can be done using hydro, wind,
wave, tidal, coal, oil gas, nuclear, biomass or geothermal power. In this way movement energy is
transformed into electrical energy. This electrical energy can then easily be transported along the
National Grid to homes, schools and industry. Every time an appliance is turned on, a magnet
somewhere has to work a little harder to provide the energy!
Please use this page for notes and revision.