Electricity Flashcards
What is electric current?
The rate of flow of charge.
What is Potential difference?
The energy transferred per unit charge
What is resistance?
How difficult it is for charge carriers to pass through a component.
What is Ohm’s law?
Current is directly proportionate to the potential difference.
What does resistivity measure?
How easily a material conducts electricity.
What is a superconductor?
A material at which below a certain temperature there is zero resistivity.
How do you add resistance in series?
Rt = R1 + R2 + R3
How do you add resistance in parallel?
1/Rt = 1/R1 + 1/R2 + 1/R3
What is power?
The energy transferred over time.
What are the features of a series circuit?
The current is the same everywhere in the circuit
The total sum of the voltages across all elements is equal to the supply p.d
What are the features of a parallel circuit?
The sum of the currents in each parallel set of branches is equal to the total current.
The potential difference across each branch is the same.
What is kirchoff’s first law?
The total current flowing into a junction is equal to the current flowing out of that junction.
What is kirchoffs second law?
The sum of all the voltages in a series circuit is equal to the battery voltage.
How does internal resistance occur?
When electrons collide with atoms inside the battery energy is lost.
What is EMF?
The energy transferred by a cell per coulomb of charge
