Electricity

Question 1

Current

Answer 1

Electrons move from negative end of cell -> positive end = flow of electrons = current
Measured with an AMMETER
symbol is I
units is AMPS (A)

Question 2

Potential difference

Answer 2

Current flows + transfers energy from cell -> component
Amount of energy transferred per unit charge = potential difference / voltage
Symbol= V
Units = Volts (V)
Measured by a VOLTMETER
MUST BE CONNECTED IN PARALLEL WITH COMPONENT as it measures how much energy goes in to a component compared with how much comes out

Question 3

Ammeter

Answer 3

Measures electric current

Can go anywhere as electric current is the same everywhere (in a series circuit)

Question 4

Series circuits

Answer 4

Series: where all components are in a long chain , one after the other. The current has to pass through every component
Disadvantage: if one bulb breaks, everything will stop working
1. More bulbs added the dimmer they are. Increases resistance
2. Current same everywhere
3. Voltage shared between bulbs

Question 5

Parallel circuits

Answer 5

Parallel : where there are branches in the circuit so the current takes different routes back to power supply
If one bulb breaks, others stay lit. Each bulb has same brightness.
Disadvantage: battery runs out faster
Adding more branches does not affect brightness of bulbs
The current splits at each branch
The total voltage is same in each branch

Question 6

Resistance

Answer 6

Electrical resistance reduces current in circuit
Adding more components increases total resistance in the circuit
Components different amounts of resistance R
Measured in Ohms (omega)

Question 7

The resistance of a material can be found using…

Answer 7

Ohms Law
Current of component is directly proportional to the potential difference across it (when it stays at the same temperature)
Resistance= potential difference (V) divided by CURRENT (I)
V= IR