Investigating Resistance Flashcards
What is resistance in an electrical circuit?
How difficult it is for current to flow through part of the circuit.
What is the purpose of the practical investigation of resistance?
To find out the resistance of a wire.
Name three factors that can affect the resistance of a wire.
- Length of the wire
- Thickness of the wire
- Temperature of the wire
What happens to resistance as the length of the wire increases?
The resistance increases.
What effect does increasing the thickness of a wire have on resistance?
The resistance decreases.
How does temperature affect the resistance of a wire?
The higher the temperature, the more resistance.
What does a voltmeter measure?
The potential difference.
What does an ammeter measure?
The current.
Why must the power pack be kept on a low potential difference?
To prevent the wire from getting very hot, which could cause burns.
Explain how temperature affects resistance.
As the wire gets hot, the ions inside the wire vibrate faster, leading to more collisions with electrons, making it harder for electrons to flow.
Why is it important to switch off electricity between readings?
To let the wire cool down, as temperature affects resistance.
What is a potential error that could cause ammeter/voltmeter readings to be too high?
A Zero error - the meters need to be set at zero to start with.
What are some factors to consider regarding measurements in experiments?
- Resolution of measurements
- Repeatability
- Reproducibility
- Control variables
Fill in the blank: The ________ stick measures the length of wire that the current is going through.
metre
