P4.3 Potential difference and resistance Flashcards
1
Q
How is an ammeter connected?
A
In series - and measure the current through the wires
2
Q
What is milliamperes?
A
1mA = 0.001 A
3
Q
How is the voltmeter connected ?
A
Parallel with the wire - measures the potential difference
4
Q
What is the equation for potential difference across a component?
A
Energy transferred, E / charge, Q
5
Q
What is the equation for resistance?
A
Resistance in Ohms = Potential difference / current
6
Q
What is Ohm’s law?
A
The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor
7
Q
What is an ohmic conductor?
A
Its resistance stays constant as the current changes - provided its temperature is constant
8
Q
What does reversing the potential difference do?
A
Reverses the current
