Physics Final Assesment Vocab

a neutral metal sphere is touched by a negatively charged metal rod. during the process, electrons are transferred from the _____ to the _____ and the sphere acquires a _____ charge.

charged rod, neutral sphere, negative

where the field lines are __________, the strength is great.

close together

charging by induction - conductors

conductors have electrons that move toward or away from the charged object (depending on the sign of the object's charge)

which spectra can be used to get information about the temperature of an object?

continuous soectrum

fusion occurs in the...

core

imagine there is a current carrying the wire staring at your computer screen and going towards you. if the current in that wire was moving towards you, the magnetif field arounf the wire is _____ from your perspective.

counterclockwise

as the distance between magnets increases, the strength of the force between the magnets will...

decrease

what will cause the current through an electrical circuit to decrease?

decreasing the voltage; increasing the resistance

when an object gains or loses charge, only the _________ move.

electrons

a glass rod is rubbed with a piece of wool. the wool has a greater electron affinity.

electrons move from the glass rod to the wool

a positvely charged balloon is held near a neutral conducting sphere. the sphere is then touched on the opposite side.

electrons move from the hand to the sphere

a negatively charged rod is held near a neutral conducting sphere. the sphere is touched on the opposite side.

electrons move from the sphere to the hand

a positively charged balloon is touched to a neutral conducting sphere.

electrons move from the sphere to the positve balloon

what direction does the magnetic field line point?

in the direction the north pole of a magnet (or compass, which is a magnet) will point when in the field.

what does grounding a charged object do?

it will allow electrons to flow to or from the object from a very large source (i.e. the ground).

triboelectric charging

rubbing two objects together and allowing them to transfer electrons from one object to another.

what ways can elements heavier than helium be created?

supernovae

explain why a negative charged ballon can stick to a neutral wall.

the charge polarizes atoms near the surface of the neutral wall (an insulator), and the atoms have more of their positive charge near the surface (although some atoms have a total neutral charge).

the ionization energy decreases as...

the effective nuclear charge decreases

the average size of an atom decreases as...

the effective nuclear charge increases

electic potential

the electric potential energy per charge in an electric field (units: V)

the effective nuclear charge is based on...

the number of protons and shielding electrons

the charge of a proton is...

+1.6 x 10^-19 C

the charge of an electron is...

-1.6 x 10^-19 C

describe the difference between conductors and insulators.

a conductor allows for the free flow of electrons inside of it, but an insolator does not.

describe how a permanent magnet is formed.

a ferromagnetic material contains domains inside of it (areas where atoms have magnetic fields in line with each other). if the ferromagnetic material is heated or tapped in a magnetic field, the domains combin and align until the material has an overall magnetic field along two poles.

how is electic current generated?

an electric current can be induced in a conductor by a changing magnetic field. often, this takes the form of a loop of wire rotating in a magnetic field; as the loops of wire rotates the amount of the magnetic field (the flux) going through the loops changes, and a curretn is induced in the side of the loop.

charging by conduction

bringing a charged object in contact with a conductor to allow it to give or take electrons from the conductor.

charging by induction

bringing a charged object near an electrically neutral object without contact.

which spectra can be used to get information about the compisition of an object?

emission spectrum and absorption spectrum

what are some effects grounding has on an electrically charged object?

for most objects, it will leave them electrically neutral. for a polarized conductor, it can allow it to become positively or negatively charged as excess charge flows from to or from the object.

the sun produces energy through..

fusing hydrogen to make helium

the sun is mostly...

hydrogen

why is light referred to as an electromagnetic wave?

light is made up of an oscillating electric and magnetic field at a right angle to each other. this is one of the reasons light does not require a medium to prorogate through since it is just oscillating magnetic and electric fields.

what is true of static charges?

like charges repel; opposite charges attract; a positively charged object has lost electrons; a negatively charged object has gained electrons

what are tiny groups of iron atoms with a common magnetic field called?

magnetic domains

stars that are fusing hydrogen in their core are...

main sequence stars

if an electroscope, charged up with excess negative charge, is touched and grounded, then it will end up with a _____ charge.

neutral

the magnetic field lines represent the direction a ______ would go if placed in the field.

north pole

if the voltage across a circuit is quadrupled, then the current through the circuit would be...

one-fourth as much

if the resistance of a circuit were tripled, then the current through thr circuit would be...

one-third as much

inside the sun, the material that makes up the sun is a...

plasma

the direction of current is defined as the direction a _________ charge moves.

positive

the direction of the electric field is the direction a __________ charge would move if placed in it.

positive

during a physics lab, a plastic strip was rubbed with cotton and became positively charged. the correct explanation for why the plastic strip becomes positively charged is that...

the plastic strip lost electrons to the cotton during the charging process.

resistance

the quality of a material that acts against the current (units: Ω)

current

the rate of the flow of charge (units: 1 A = 1 C/s)

current (the movement of charge)

the source of all magnetism

how are magnets like electric charges?

they can both attract and repel without touching.

what are the three ways objects can gain or lose charge?

triboelectric charging, charging by induction, and charging by conduction.

there is a stronger electric field between...

two opposite charges of the same magnitude

the sun will leave behind a...

white dwarf

what happens if you cut a permanent magnet in half?

you end up with two magnets, each with a north and south pole.