# Progress Checkpoint P4

### Progress Checkpoint P4

###### Published on 1 November 2022

Physics Progress Checkpoint about electricity 1/11/22

DR
##### Doug Reynolds
Doug's Personal Gallery
##### Transcript
00:00
What is electrical resistance and how is it measured?
00:00
Progress Checkpoint P4
00:06
Key Question 1: What symbols are used to represent electric components?
00:23
Key Question 2: How is charge calculated?
00:27
To calculate the charge, you divide the work done in joules over a certain amount of time by the voltage.
00:31
The Big Question: What is electrical resistance?
00:34
What is meant by potential difference?
00:34
The difference of electrical potential between two points.
00:34
What is used to measure potential difference?
00:34
A voltmeter.
00:34
What are the units for potential difference?
00:34
Potential difference is measured in volts.
00:38
What is resistance in an electrical circuit?
00:38
Resistance is a force that counteracts the flow of current.
00:38
What causes resistance in an electrical circuit?
00:38
Resistance is caused when the moving electrons collide with ions in the metal.
00:38
What are the units for resistance?
00:38
Resistance is measured in ohms with a symbol of: Ω
00:44
How is resistance calculated?
00:44
R = V ÷ I
00:44
To calculate the resistance, you divide the voltage by the current.
00:49
How can resistance be increased?
00:49
The resistance in a wire can be increased by increasing the length of the wire or making the wire thinner.
00:49
How can resistance be overcome?
00:49
By using thicker wires to give the electricity more space to run.
00:54
What is Ohm's law?
00:54
According to BBCBitseize, Ohm's law states that 'the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions, such as temperature, remain constant.'
00:60
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