ipc ch.20

What is electric charge?

a property that causes subatomic particles such as protons and electrons to attract or repel each other

What happens to an atom when it gains electrons?

it becomes a negatively charged ion

What is the relationship between electric force and net charge?

the electric force is directly proportional to the net charge on each object

How does distance affect electric force?

the electric force is inversely proportional to the square of the distance between the objects

Electric force

the force of attraction or repulsion between electrically charged objects

What is an electric field?

the effect an electric charge has on other charges in the space around it

What direction does the electric field around a positive charge point?

outward

What direction does the electric field around a negative charge point?

inward

What is static electricity?

the study of the behavior of electric charges

What does the law of conservation of charge state?

the total charge in an isolated system is constant

What is charging by friction?

a process where electrons move from one object to another due to friction, causing one object to become negatively charges and the other positively charges(balloon on head)

How does charging by contact work?

when a charged object touches an uncharged object, some of the charge is transferred, reducing the original objects net charge

What is charging by induction?

the transfer of charge without contact between materials, such as when walking on a carpet builds a negative charge on your body that repels electrons in a metal doorknob

Induction

transfer of charge without contact between materials

When does static discharge occur?

when a pathway through which charges can move forms suddenly

Why do you get a shock from a doorknob?

the spark felt is a static discharge, where air becomes charged providing a path for electrons to flow

What is electric current?

the continuous flow of electric charge

What is the difference between direct current (DC) and alternating current (AC)?

DC flows in one direction while AC regularly reverses its direction

What is the SI unit of electric current?

ampere(A)

How is electric current defined despite electrons flowing in the opposite direction?

the direction in which positive charges would flow

What is an electrical conductor?

a material through which charge can flow easily

What is an electrical insulator?

a material through which charge cannot flow easily

What is resistance

opposition to the flow of charges in a material

What happens to electrons as they move through a conducting wire?

the collide with each other, and with ions, converting some kinetic energy into thermal energy which reduces current

What is the SI unit of resistance?

ohm

What happens to resistance as the length of a wire increases?

resistance increases because charges travel farther

What is a superconductor?

a material that has almost zero resistance when cooled to low temperatures

What is potential difference?

the difference in electrical potential energy between two places in an electric field, measured in joules per coulomb or volts

What does Ohm's Law state?

V=ixr

What tool can be used to measure current, voltage, or resistance?

multimeter

What is an electric circuit?

a complete path through which charge can flow

What does a circuit diagram represent?

one or more complete paths in which charge can flow, with arrows indicating the direction of current

What happens in an open circuit?

the circuit is not a complete loop, and current stops flowing

What happens in a closed circuit?

the circuit is complete and charge can flow

What is a series circuit?

charge has only one path through which it can flow

What effect does adding bulbs to a series circuit have?

increases the resistance, decreases the current, and causes each bulb to be dimmer

What is a parallel circuit?

a circuit with two or more paths through which charges can flow

What happens if one bulb in a parallel circuit burns out?

charge still flows along the other path and the other bulb stays lit

What is electric power?

the rate at which electrical energy is converted to another form of energy

What is the unit of electric power?

joules per second, or Watt(W)

How do you calculate power

P=ixv

What is a fuse and how does it work?

prevents current overload in a circuit, it melts if too much current passes through

What is a circuit breaker?

a switch that opens when current in a circuit is too high and must be reset

What safety measure is taken to protect people from electrical shocks?

electrical wiring is insulated

What should you avoid doing to prevent electrical shocks?

avoid touching electrical devices with wet hands

What is grounding in electrical safety?

the transfer of excess charge througha conductor to earth