Resistance and V=IR - PRACTICAL Flashcards
Electricity (17 cards)
What is the formula linking potential difference and current?
V = I x R
R is Resistance
If a 4.0 Ω resistor has a potential difference of 6.0 V across it, what is the current through the resistor?
1.5 A
What does an ammeter measure?
The current (in amps) flowing through the test wire
How must an ammeter be connected in a circuit?
In series with whatever you’re investigating
What does a voltmeter measure?
The potential difference (or pd) across the test wire (in volts)
How must a voltmeter be connected in a circuit?
In parallel around the test wire
What is one factor that can affect the resistance of a circuit?
The length of wire used in the circuit
What happens to resistance when the length of the wire increases?
Resistance is directly proportional to length
Fill in the blank: Resistance is directly proportional to _______.
length
What should be done if the graph of resistance against wire length does not go through the origin?
It could be due to a systematic error in length readings
What is the relationship between resistance and wire length shown by the graph?
A straight line through the origin
What should be done between measurements to ensure accurate resistance readings?
Leave the switch open for a bit to let the circuit cool down
What is the formula for calculating resistance from current and potential difference?
R = V / I
What is the use of a crocodile clip in the experiment?
To attach to the wire at measured intervals
What is a systematic error in the context of measuring wire length?
All length readings are slightly out due to incorrect attachment
What is the potential difference measured in?
Volts
What type of circuit connection can affect resistance?
Whether components are in series or parallel
