Studied by 5 people
Static electricity
the build up of excess electric charge on an object
Electric field
exerted by a charged object; allows us to charge by induction
Electroscope
device that detects electrical charge on an object
Conductor
material that allows electrons to flow easily
Insulator
material that blocks the flow of electrons
Static discharge
the flow of electricity between two electrically charged objects caused by contact Ex. Lightning
Grounding
providing a path that allows electrical charges to travel directly into the Earth instead of into a building
List the 3 subatomic particles, their charges, and where they are located in an atom.
Protons = (+) = in the nucleus
Neutrons = (0) = in the nucleus
Electrons = (-) = surrounding the nucleus
Describe the 3 “rules” of charge.
Opposite charges attract
Like charges repel
Law of Conservation of Charge = charge can never be created or destroyed, it only changes forms.
Provide examples of materials that make good conductors vs. insulators.
Conductors = metals and skin
Insulators = rubber, plastic, Styrofoam
Explain the three ways charge can be transferred.
Conduction: transfer of e- through direct contact between objects.
Friction: transfer of e- through rubbing objects.
Induction: transfer of e- through electric
fields working over a distance.
Explain how lightning works.
Movement of clouds causes build up of static electricity in clouds.
When e- build up enough, it induces a (+) charge on Earth.
Attraction becomes great enough e- travel from the clouds to Earth to neutralize.
Current
the net movement of electric charges in a single direction
Voltage difference
the push that causes charge to move
Resistance
the tendency of materials to oppose the flow of electrons through it
Ohm’s Law
the current in a circuit equals voltage difference divided by resistance
Differentiate between the effects of an open vs. closed circuit.
Open 🡪 current cannot flow.
Closed 🡪 current can flow.
Explain how a battery works.
Chemical reactions create a voltage difference between terminals, which pushes the current from the (-) terminal to the (+) terminal.
Describe the 4 factors that affect resistance.
Temperature (higher temp, more KE, therefore more resistance)
Material (conductors decrease resistance, insulators increase it)
Length (longer the wire the more the resistance)
Diameter of wire (thinner the wire the more the resistance)
Explain the relationship between voltage, current and resistance in a circuit.
An increase in voltage causes an increase in current because the push is greater so charge is pushed through more.
A decrease in resistance causes an increase in current because e- can flow easier.
Circuit
closed path through which electrons can flow
Ammeter
device that measures the amount of current in a series circuit
Voltmeter
device that measures the voltage drop in a parallel circuit
Fuse
small piece of metal that melts when a circuit is overheated and causes the circuit to open so that current can no longer flow
Circuit breaker
small piece of metal that bends when a circuit is overheated and causes the circuit to open so that current can no longer flow
Series vs. Parallel
Series (one branch) simple (one goes out, the rest go out)
Parallel (multiple branches) complex
Magnetism
property of some materials that allows them to give off an attractive or repulsive force
Magnet
a material that gives off an external magnetic field, making it possible to apply a force over a distance
Magnetic field
external force given off by a magnet; strongest at the poles.
Ferromagnetism
phenomenon where objects placed in a strong magnetic field become magnetized due to the poles within their atoms aligning (all e- in same direction).
Electromagnet
temporary magnet made by placing a piece of iron inside a current carrying coil of wire.
Electric motor
device that uses an electromagnet to convert electrical energy into mechanical energy.
Generator
device that uses an electromagnet to convert mechanical energy into electrical energy.
Describe the force that exists between magnetic objects. Include where it is the strongest, and how this force acts similarly to other forces we’ve learned about.
Force between magnetic objects is the magnetic field.
It is strongest at the poles.
It is similar to electrical force in that opposites attract and like repel.
It is similar to gravitational force in that the closer you are to it, the stronger it feels.
Explain the relationship between magnetic fields and magnetic force.
Magnetic fields are the external forces given off by magnets. They make it possible to apply a force over a distance.
Differentiate between the magnetic domains on magnetic elements vs. nonmagnetic elements.
Magnetic elements have aligned magnetic domains, nonmagnetic do not.
Explain the relationship between electricity and magnetism.
Electrical current can produce a magnetic field, counterclockwise from the direction the current is traveling.
List the two ways to increase the strength of an electromagnet.
Increase the number of loops.
Increase the strength of the current.
Note
Flashcard