Unit 9 - Energy, Power and Resistance Flashcards
What is potential difference?
A measure of energy transferred per unit charge. The energy transferred by the charge carriers.
What unit is potential energy?
Volts (V)
What is the Equation for voltage using Work done and charge?
V = W/Q
Why do you put a voltmeter in parallel?
The voltmeter will have a very high resistance (infinite) so no current can pass through.
What is one volt?
The energy transferred per Coulomb of charge as the charges move between two points in a circuit.
What is Electromotive force (EMF)?
The energy transferred to the charge carriers (by cell/battery)
What is the difference between EMF and Potential difference?
EMF is energy transferred to charge carriers.
PD is energy transferred by charge carriers.
What is the equation for EMF?
e = W/Q
(Same equation and units as potential difference equation)
What is resistance?
Measure of the opposition to current flow in an electrical circuit.
What is the equation for resistance?
R = V/I
What is the resistance of a component?
the ratio between the potential difference across a component and the current flowing through it.
What is Ohm’s law?
For a metallic conductor at constant temperature the potential difference across the conductor is directly proportional to the current flowing through the conductor.
What does resistance depend on?
Length, Cross sectional area, Material, Temperature
How is resistance affected by length?
Resistance is directly proportional to the length
How is resistance affected by the cross sectional area?
Inversely proportional to the cross sectional area.
