11: Electrical Circuits Flashcards
Define potential difference
It represents the amount of energy that charge carriers have between these points and is measured in volts (V).
Formula relating work and volts
V=W/q
What happens to a positive charge released in an electric field?
It accelerates in the direction of decreasing potential, gaining kinetic energy equal to qV
qV, where V is the potential difference.
What is the difference between conductors and insulators?
Conductors: Materials with many free electrons, allowing easy charge flow (e.g., metals).
Insulators: Materials with very few free electrons, preventing charge flow (e.g., plastics).
Define electric current and its unit.
Electric current (I) is the rate of flow of charge in amperes
Define Electricity
Measure of the opposition to the flow of electric current in a circuit.
What is Ohm’s Law?
At constant temperature, current through a conductor is proportional to the potential difference. FOR OHMIC MATERIALS.
V=IR
What causes resistance in a metal?
Resistance is due to collisions between free electrons and metal atoms, converting electrical energy into heat.
How does temperature affect resistance in metals?
Increasing temperature increases atomic vibrations, leading to more electron collisions and higher resistance.
What is electromotive force (emf)?
Emf is the work done per unit charge to move charge between terminals of a source. In VOLTS
What is the total resistance for resistors in series?
The total resistance is the sum of individual resistances: Rtotal=R1+R2+R3
What is the total resistance for resistors in parallel?
1/Rtotal= 1/R1 + 1/R2 …
How are ammeters and voltmeters connected in a circuit?
Ammeter: Connected in series, ideally with zero resistance.
Voltmeter: Connected in parallel, ideally with infinite resistance.
What is a potential divider?
A circuit that uses resistors to provide a variable output voltage from a fixed input voltage
