1.1 When you rub a balloon it becomes
electrically charged and attracts other
1.1.1 You charge any other
insulating materials in a
1.1.2 An object get charged when it
gets covered in negitively
1.1.3 The potential difference (p.d.), or voltage, between two points
in a circuit is work done, or energy transfered, per coulomb of
charge passing through the circuit.
126.96.36.199 V = W/Q
188.8.131.52.1 V is the p.p in volts (V), W is the work done in joules
(J) and Q is the electrical charge in colombs (C).
2 3.2 Current, potential
difference and resistance
2.1 Ohm's law: V = IR
2.1.1 V = potential difference in volts (v), I
= current in amps (A) and R =
resistance in ohms (Special Omhs
2.2 LDRs is a light dependant
resistor. It is a resistor to
control the flow of current in a
3 3.3 Non-ohmic conductors
3.1 Some components don't follow Ohm's law. For example a filament bulb is a ordinary
bulb. The tungsten filament in the bulb conducts electricity well. But its resistance
changes the hotter it gets. the more current, the hotter it gets. Meaning its harder to
push the current through the circuit.
3.2 LEDs are a even more efficient than other bulbs as they last for
hundreds of times longer than filament bulbs . But they are very
4.1 In a series circuit, the total p.d. from the power
supply is shared between the components.
4.1.1 Potential difference across each resistor = total p.d. x
resistance of resistor/ total resistance
5 3.5 Parallel Circuits
5.1 it contains at least one place
where the circuit splits into two
or more seperate currents.
5.2 the p.d. is the same across each
component of a parallel circuit.
5.3 The resistance of each
branch determmines how the
5.3.1 the larger the resistance of the
branch, the smaller the current