What is an electric current?
An electric current is a flow of microscopic particles
called electrons flowing through wires and
components.
+
-
In which direction does the current flow?
from the Negative terminal to the Positive terminal of a
cell.
Electrical Charge and Current
Learning Outcomes:
1. I can recall and apply the equation for charge
2.
I can apply the equation for charge to show how
we can increase or decrease current in a circuit
3.
I can apply the equation for charge flow to an
exam style question
Electric current

Electric current is a flow of electrical
charge carried by electrons which move
from the negative terminal to the positive
terminal.

The size of the electric current is the rate
of flow of electrical charge.
Electrical Charge

Stand up and move around to make a circle
around the room.

Now start walking around in the circle.

Stop – what are you in the circuit?

Think about this analogy – if you are the
electrons carrying the charge, how could
you work out the charge?
Charge

Charge (Q) = Current (I) x Time (t)

Q=It

Units:
◦ Charge (Q) is in Coulombs (C)
◦ Current (I) is in Amps (A)
◦ Time (t) is in Seconds (s)

Can you draw a formula triangle for this?
Examples:
1.
A current of 12A passes through a
kettle for 20s. How much charge has
flowed through the kettle?
Answer: Q =It = 12 x 20 = 240C
2.
A current of 200A passes through a
hoover for 10minutes. How much
charge has flowed through the kettle?
Answer: Q=It = 200 x (10x60) =12,000C
3.
A charge of 200C flows through an iron
for 10s. What is the current?
Answer: Q=It, I= Q/t = 200/10 = 20A
Moving charges worksheet

Have a go at the worksheet on charges
and Q=It.
Current

If Q = It, how could we INCREASE or
DECREASE the current in a circuit?

Hint: Try rearranging the equation to
make current the subject of the
equation.....
Answer...

Q=It so I=Q/t.
This means that the current increases if:
1. You INCREASE the charge, or
2. You decrease the time.


(Thinking back to our moving round the
room analogy – if you ran, you would pass
the front more times, if you walked around
a smaller room, you would too.)
Exam question

Have a go at the exam question on charge
and current.

Once you are done, write a question for
the person next to you.
Just a minute


With the person next to you, you are going
to play a game of just a minute...
Rules:
◦ First person talks for a minute about current and
charge without:
◦
◦
1. Repetition – repeating yourself
2. Hesitation – saying ‘erm’ or long gaps
3. Deviation – talking about something unrelated
If you do any of this, and the other person
buzzes you, the other person has the remaining
time to talk about it.
The person who is talking at the minute mark
wins!