# Shared Flashcard Set

## Details

Chapters 22 and 23
Electricity
49
Physics
03/24/2013

Term
 What is an electric current? What are the two types of current?
Definition
 the flow of charge; AC and DC
Term
 What does AC mean? HOw does it move?
Definition
 alternating current; moves back and forth
Term
 What does DC mean? HOw does it move?
Definition
 direct current; moves in the same direction
Term
 What is the unit for current? What is the symbol for current?
Definition
 Amp (A); I
Term
 What is electric potential?
Definition
 the difference in potential energy between two points
Term
 What are other names for electric potential?
Definition
 potential difference, potential drop, EMF, voltage
Term
 What is the unit for electric potential?
Definition
 volt
Term
 What are fives sources of electric potential?
Definition
 electromagnetic induction, photoelectric effect, thermoelectric, piezoelectric, chemical effect
Term
 What type of energy is converted in electromagnetic induction? What is an example of something that uses electromagnetic induction?
Definition
 mechanical energy converted to electrical energy; example is a generator
Term
 What type of energy conversion takes place in the photoelectric effect?
Definition
 light energy to electricity
Term
 What type of energy conversion takes place in the thermoelectric effect?
Definition
 heat is converted to electricity
Term
 What type of energy conversion takes place in the piezoelectirc effect?
Definition
 mechanical energy to electricity
Term
 What type of energy conversion takes place in the chemical effect?
Definition
 chemical energy to electric
Term
 What is an example of the piezoelectric effect?
Definition
 gas grill starter
Term
 practice voltage and current drawings (batteries)
Definition
Term
 What is resistance?
Definition
 loss of energy or opposition to current
Term
 What are four factors that affect the resistance?
Definition
 length, area, resitivity, temperature
Term
 What is the unit for resistance?
Definition
 ohms
Term
 How does the length of the wire affect the resistance?
Definition
 the longer the wire, the more resistance
Term
 How does area affect resistance?
Definition
 the more area, the less resistance
Term
 How does the resitivity affect resistance?
Definition
 the lower the resitivity, the better conductor
Term
 HOw does temperature affect resistance?
Definition
 as temperature increases, resistance also increases
Term
 What is the equation to calculate the resistance of a piece of wire?
Definition
 R=pl/A A=pir squared
Term
 How do you read the resistance of a resistor?
Definition
 look at the colors--do not add the numbers, just put them together and multiply by the third number
Term
 What is Ohm's law?
Definition
 I=V/R or V=IR
Term
 The smaller the wire the, ____resistance.
Definition
 more
Term
 What are three things you must have for a circuit?
Definition
 source of voltage (EMF), conductors to complete the pathway, load
Term
Definition
 something that is being run by the circuit
Term
 study circuit symbols
Definition
Term
 How do you calculate electrical power?
Definition
 P=w/t=VI=I2R=V2/R
Term
 How do you calculate electrical energy?
Definition
 energy = power x time
Term
 What is a kilowatt hour?
Definition
 a unit of energy equal to the work done by a power of 1000 watts operating for one hour
Term
 How do you calculate cost?
Definition
 cost = energy x rate (energy is in kilowatt hours)
Term
 Which way do electrons flow in conductors?
Definition
 from negative to positive
Term
 Which way does conventional current flow?
Definition
 positive to negative
Term
 One coulomb is equal to how many electrons?
Definition
 6.25 x1018 electrons
Term
 sample problem one on review sheet
Definition
Term
 If electrons are moving north, in which direction is the current moving?
Definition
 moving south
Term
 What is drift velocity?
Definition
 the speed of the electrons (very slow)
Term
 What is EMF?
Definition
 electromagnetic force
Term
 What is the symbol for a cell?
Definition
 short line is a cathode (-); long line is an anode (+)
Term
 When cells are connected in a series, what increases?
Definition
 voltage
Term
 When cells are connected in parallel, what increases?
Definition
 current
Term
 What is resitivity? What is the symbol?
Definition
 measure of the resistance per length; symbol is p (rho)
Term
 The number of charges passing a point in a second is called the _____
Definition
 electric current
Term
 What causes charge to flow?
Definition
 voltage or potential difference
Term
 If the length of wire increases what happens to the resistance?
Definition
 it increases
Term
 IF the width of the wire increases, what happens to the resistance?
Definition
 it decreases
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