Physics - Electricity & Electromagnetism Q1

alternating current (AC)

electric current that changes direction in cycles as the electric potential of the source changes

anmeter

device that measures current; must be wired in series

ampere (A)

unit of electric current; 1A = 1 C/s

capacitor

device that temporarily stores an electric charge

circuit

closed pathway for electricity to flow

series circuit

elements are wired along a single pathway in a conductor; current is the same across each resistor

parallel circuit

elements bridge or branch across a conductor; voltage is the same across each resistor

conductor

material with an abundance of free electrons that allow free flow of electricity (Cu, gold, water)

coulomb (C)

SI unit of electric charge; 1C = 6.25 × 10¹⁸ electrons

coulomb’s law

F= k(Q1)(Q2)/ r2; force between charges is proportional to their quantities and inversely proportional to the square distance

current

flow of electrons in a conductor measured in Amperes (1C flowing by a given point in 1 sec or the amount of current flowing with 1V in a circuit with 1 ohm)

direct current (DC)

electric current flowing in one direction only

electric potential (voltage)

ability to do work due to separation of charges; measured in Volts (V)

grounding

process of connecting an electrical device to earth via a conductor to neutralize it

induction

creating a current in a secondary uncharged conductor when a primary conductor supplied with AC is in close proximity but not touching the secondary conductor due to the creation of a moving magnetic force in the primary conductor when electricity is flowing

insulator

material with tightly bound electrons that do not allow electricity to flow even when attracted by a potential difference (rubber, plastic, glass, wood)

Ohm

amount of resistance in a circuit

Ohm’s law

V=IR; voltage equals current times resistance

power (P)

rate of doing work; P= IxV; measuring in Watts

resistance (R)

opposition to current flow, measured in ohms

semiconductor

materials that will conduct and insulate electricity but not as well as conductors and insulators

superconductor

material that has no resistance to electron flow (very low temps- Ohms law will not apply)

volt (V)

unit of electrical potential (1V = J/C)

voltmeter

measures voltage in a circuit, must be wired across the main circuit (in parallel)

watt

a unit of power (W/t), equivalent to a J/s; 1A of current flowing through 1V

battery

produces electrons through a chemical reaction, stores an electric charge long term & provides an electric potential - direct current

capacitor

temporarily stores an electric charge

diode

a ‘‘one way valve’’ device; allows electrons to flow in only one direction

fuse & circuit breakers

emergency devices that break or open the circuit if their is a sudden surge of electricity to the circuit or device

resistor & rheostat

inhibits the flow of electrons, thereby precisely regulating the flow of electricity through that part of the circuit where it is located

switch

device that opens a circuit (breaks the pathway)

transformer

device that can increase or decrease voltage by a predetermined amount

ammeter

measures current (must be in a series)

voltmeter

measures potential difference btw 2 pts (voltage); must be in parallel