# Shared Flashcard Set

## Details

Magnetism and Electricity
Main ideas for studying.
42
Physics
01/24/2012

## Additional Physics Flashcards

Term
 Name three kinds of electric charges.
Definition
 Positive, negative and neutral/no charge.
Term
 What type of charges attract?
Definition
 Opposite charges.
Term
 What type of charges repel?
Definition
 Like charges.
Term
 What type of resistance does a conductor have?
Definition
 Low resistance.
Term
 What type of resistance does an insulator have?
Definition
 High resistance.
Term
 What is potential difference measured in?
Definition
 Volts/Voltage.
Term
 What is electric current?
Definition
 Electric current is the rate at which electricity flows through a wire.
Term
 What is electric current measured in?
Definition
 Amps/Amperes.
Term
 What causes resistance?
Definition
 Internal friction causes resistance.
Term
 What does resistance do to charges going through objects?
Definition
 Resistance slows the movement of the charges.
Term
 What is the difference of currents?
Definition
 Resistance.
Term
 What is the resistance equation?
Definition
 R=V/I
Term
 What is a semiconductor?
Definition
 A semiconductor is a material that has both conducting and insulating properties.
Term
 How do semiconductors act in their pure state?
Definition
 They act a insulators.
Term
 What do impurities in semiconductors do?
Definition
 They increase it's conducting abilities.
Term
 What are some well known semiconductors?
Definition
 Silicon and geranium are two common semiconductors.
Term
 What is a series circuit?
Definition
 It is a circuit in which the paths are joined one after another such that the current in each part is the same and have a single path for current, voltage can be different because resistance can be different
Term
 What is a parallel circuit?
Definition
 It is a circuit in which the paths are joined in branches such that the potential differences across each part id the same and have multiple paths for currents, the current for each does not have to be the same
Term
 What is the electric power equation?
Definition
 P=CV
Term
 What is the function of fuses and circuit breakers?
Definition
 They are safety devices that prevent overloads in electric devices.
Term
 What is a fuse?
Definition
 A fuse is an electric device that contains a metal strip that melts when current in the circuit becomes to great.
Term
 What is a circuit breaker?
Definition
 A circuit breaker is a switch that opens a circuit automatically when the current exceeds a certain value, uses a bimetallic strip or magnet that responds to current overload
Term
 Where on a magnet is the magnetic force strongest?
Definition
 Near the poles.
Term
 True or False:All magnets have at least one North and South pole.
Definition
 True.
Term
 What is a magnetic field?
Definition
 A region where magnetic force can be detected.
Term
 What do magnetic field lines represent?
Definition
 Magnetic fields.
Term
 True or False:The closer the electric and magnetic field lines, the stronger the magnetic field
Definition
 True.
Term
 What do magnetic field lines always form?
Definition
 Closed loops.
Term
 Where do Earth's field lines run from?
Definition
 From geographical North to geographical South.
Term
 What two properties do all fields have?
Definition
 A direction and a strength.
Term
 What is the Right-Hand Rule?
Definition
 Rule: if you hold a wire in your right hand and point your thumb in the direction of the positive current, the direction that your fingers curl is the direction of the magnetic field
Term
 How do you create an electromagnet?
Definition
 By passing a current through a wire wrapped around a piece of iron which creates a magnetic field in the iron rod.
Term
 What do both generators and electric motors do?
Definition
 They both create energy.
Term
 What does a generator specifically do?
Definition
 A generator turns mechanical energy into electrical energy.
Term
 What does an electric motor specifically do?
Definition
 An electric motor turns electrical energy into mechanical energy.
Term
 Describe electromagnetic induction.
Definition
 Electromagnetic induction is when a current is created by changing magnetic fields.
Term
 What is an alternating current/AC?
Definition
 A current that is constantly changing from a negative to a positive charge.
Term
 What is a direct current/DC?
Definition
 The charge is always the same.
Term
 How does the loop move in an AC?
Definition
 For each half rotation on the loop the current that changes direction at regular intervals.
Term
 When the loops are perpendicular to the field what is the current?
Definition
 The current is 0.
Term
 How does a transformer work?
Definition
 It works by having the primary coil induce a magnetic field causing a different voltage to be created in the secondary coil.
Term
 More coils in the secondary circuit=?
Definition
 Increased voltage and vice-versa.
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