Current Electricity

Question 1

What is an Electric Current?

Answer 1

~ Caused by the flow of electrons through a good conductor such as metal
~ A good insulator does not allow electric current to flow

Question 2

Electric Charge

Answer 2

~ an electric current is a flow of electric charge

Question 3

Conductor

Answer 3

~ Conductors are substances which allow electric current to flow through them freely

Question 4

Insulators

Answer 4

~ Insulators are substances which do not allow electric current to flow through them.

Question 5

Electrical Energy Can Be Converted Into…

Answer 5

~ Light:
Light energy so we can see in the dark
~ Heat:
Heat energy so we can cook + heat buildings
~ Kinetic:
Kinetic energy for electric motors
~ Sound:
Sound energy for music

Question 6

Closed Circuits

Answer 6

~ A closed circuit is needed for the current to
flow
~ If there is a break in a circuit then the
current wont flow and the electrical energy
can’t get through

Question 7

Batteries

Answer 7

• Energy provided by a battery or power
pack is needed to move the current
around the circuit
• The battery pumps electrons from its
negative end around a circuit
• The electrons travel all the way around
and are attracted back to the positive end
of the battery

• The negative end of the battery is an area
of High Electrical Pressure
• The positive end of the battery is an area
of Low Electrical Pressure
• Electrons will move from areas of High
Electrical Pressure to areas of Low
Electrical Pressure

Question 8

Potential difference

Answer 8

• The difference in electrical pressure
between the positive and negative ends is
called the Potential Difference
• Whenever there is a potential difference
electricity will flow
• This potential difference is known as
Voltage and is measured in volts

Question 9

Resistance

Answer 9

• Resistance is the opposition to the flow
of electrons. The unit is the Ohm (Ω),
and it is measured using an Ohmmeter
• If a Resistor is placed in an electric circuit,
it will slow down the flow of electrons

Question 10

Bulbs in Series

Answer 10

• Like the bulb on a christmas tree, what
happens if one blows?
• The same amount of current flows through
each bulb in the series
• The voltage is split up, depending on the
size of the bulb
• If they are the same size bulbs, then the
voltage is split evenly

Question 11

Bulbs in Parallel

Answer 11

• The lights in your house are connected in
parallel, as are car head lights
• If your bedroom light blows, is the kitchen
light affected?
• The current is split between the bulbs, if
they are the same size, then the current is
split evenly
• The same voltage flows through each bulb

Question 12

Direct Current

Answer 12

• Direct current goes in one direction only
e.g. the current from a battery

Question 13

Alternating Current

Answer 13

• Alternating current changes very quickly,
many times a second
• This is how the current is supplied by the
ESB
• AC can be converted to DC using a
rectifier, smoothed using a capacitor