__Electric Current and Potential Difference__

Describe how an ammeter is placed in series with a component to measure the current, in amps, in the component

Explain how current is conserved at a junction

Explain how the current in a circuit depends on the potential difference of the source

Describe how a voltmeter is placed in parallel with a component to measure the potential difference (voltage), in volts, across it

Demonstrate an understanding that potential difference (voltage) is the energy transferred per unit charge passed

and hence that the volt is a joule per coulomb

Explain how current is conserved at a junction

Explain how the current in a circuit depends on the potential difference of the source

Describe how a voltmeter is placed in parallel with a component to measure the potential difference (voltage), in volts, across it

Demonstrate an understanding that potential difference (voltage) is the energy transferred per unit charge passed

and hence that the volt is a joule per coulomb

__Resistance and V =I x R__

Investigate the relationship between potential difference (voltage), current and resistance

Explain how changing the resistance in a circuit changes the current and how this can be achieved using a variable resistor

Use the equation:

potential difference (volt, V) = current (ampere, A) x resistance (ohm)

V = I x R

Explain how changing the resistance in a circuit changes the current and how this can be achieved using a variable resistor

Use the equation:

potential difference (volt, V) = current (ampere, A) x resistance (ohm)

V = I x R

__Devices and Resistance__

Demonstrate an understanding of how current varies with potential difference for the following devices:

a) filament lamps

b) diodes

c) fixed resistors

Demonstrate an understanding of how the resistance of a light dependent resistor (LDR) changes with light intensity

Demonstrate an understanding of how the resistance of a thermistor changes with change of temperature (negative

temperature coefficient thermistors only)

Explain why, when there is an electric current in a resistor, there is an energy transfer which heats the resistor

Explain the energy transfer (in above) as the result of collisions between electrons and the ions in the lattice

Distinguish between the advantages and disadvantages of the heating effect of an electric current

Use the equation:

electrical power (watt, W) = current (ampere, A) x potential difference (volt, V)

P = I x V

Use the equation:

energy transferred (joule, J) = current (ampere, A) x potential difference (volt, V) x time (second, s)

E = I x V x t