Electrical quantities Flashcards
Mr. Rocha
Does the current flow from negative to positive or positive to negative?
positive to negative
Does the electron flow flow from negative to positive or positive to negative?
negative to positive
1 Ampere =
1 coulombs of charge per second
What is the unit and symbol for charge?
unit: coulomb
symbol: C
What is the unit and symbol for current?
unit: amp
symbol: A
Define voltage
the work done by charge passing through an electrical component
What is the unit for voltage?
volts
What is voltage measured by?
voltmeter
What happens if there is an ‘obstacle’ in the middle on a current?
particles waste energy going past it
Define EMF (electromotive force)
textbook definition:
the electrical work done by a source, move unit of charge around circuit: the voltage across the terminals of a source
simpler: the amount of energy provided by a power source (like a battery) to each unit of charge as it moves through a circuit. It’s like the “push” or force that makes electric charges flow around the circuit.
If cells with EMFs E1 & E2 are connected in series, their combined EMFs are given by:
E = E1 + E2
What does P.D. mean?
potential difference
1 volt =
1 J of energy to move 1 coulomb of charge
When a symbol has an arrow through it, this indicates that…
it’s variable
Describe ohmic resistor
has a constant resistance; its current-voltage characteristic is a straight line graph, so that the current through it is directly proportional to the voltage across it. can keep the temp. constant, so the current can easily increase as the voltage increases (constant resistance)