electricity Flashcards
What is current measured in
amperes
What are the units of power
The units of power are watts. The units of current are amps.
what type of current flows from batteries
DC current flows from batteries and solar cells. Mains electricity is AC.
What doesn’t pose a risk of an electric shock
Inserting a plug into a socket does not pose a risk of shock. However, inserting other objects does, perhaps surprisingly, as do long electrical cables.
what colour is the neutral wire
The neutral wire is blue. The green and yellow wire is called the earth.
Which wire sits next to the fuse in a plug?
The live wire sits next to the fuse in a plug. The earth wire sits at the top of the plug.
What units are fuses measured in?
Fuses are measured in amps. Often fuses used in sockets in our houses are 13 amps. Volts are a measure of potential difference or voltage.
What is a circuit breaker
A circuit breaker is a resettable fuse. Fuses are not resettable. When they blow they are permanently broken and need to be replaced.
Which of these describes the relationship between the current of an electrical device and its fuse rating?
The fuse rating should be slightly greater than the current of the device. It should not be less.
Ohms law
for an ohmic conductor, current is directly proportional to potential difference (voltage) provided temperature does not change
Polar and non polar meaning
Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out
How to work out a voltage graph for a filament lamp
Connect the wires to the positive and negative PSU terminals to forward biased the lamp
turn on the power supply unit (PSU)
Adjust the sliding contact on the potential divider to the lower end, so the potential difference (pd or voltage) across the lamp is zero
read the pd (voltage) using the voltmeter and the corresponding current on the ammeter
Move the sliding contact a small distance along the potential divider until the pd across the lamp is about 2 volts, read the voltmeter and ammeter.
repeat this in steps of about 2 volts for six different voltages and corresponding currents
Turn off the power supply
switch the wires in the + and - terminal of the PSU so the lamp is reverse biased
Repeat the experiment for six different values of the pd and current
resistance equation
Volts/amps
