Electricity Flashcards
What is electric current in a metal?
A flow of electrons and the electrons move in the opposite direction to that of a conventional current
What is the difference between conductors and insulators?
Conductors allow electrical current to flow through them easily.
Insulators are poor conductors which don’t allow electrical current to flow easily
What is the meaning of cell polarity?
The spatial differences in the shape, structure and function of cells
What is the equation for current, charge and time?
Charge = Current x Time
What is charge measured in?
Coulombs
What is the voltage provided by cells connected in series?
The sum of the voltages of each cell. (Having regard to their polarity)
How is the temperature of a wire kept constant?
Using a switch and small currents
What is a V-I graph?
A straight line that passes through the origin
What does a V-I graph show for current and voltage?
That they are proportional for a metal wire at a constant temperature (Ohm’s law)
What is the equation for voltage, current and resistance?
(what are the units for each of these factors?)
Voltage = Current x Resistance
Voltage=Volts
Current=Amperes
Resistance=Ohms
What are voltage for components connected in parallel?
The same as that of the supply
What is the total current taken from the supply?
The sum of the currents through the separate components
What does the resistance of a metallic conductor at a constant temperature depend on?
The area of cross section and the material it is made from
What are the equations to calculate energy, power, current, voltage, and time? (units for each of these below)
Energy = Power x Time
Power = Current x Voltage
Energy=Joules (J)
Power=Watts (W)
Current=Amps (A)
Voltage=Volts (V)
Time=Seconds (S)
What is the unit used in cost of electricity?
Kilowatt-hour
