Electricity

Atoms are made up of……

protons, neutrons, electrons

What charge are protons?

positive

What charge are neutrons?

no charge

What charge are electrons?

negative charge

What is matter made up of?

atoms

The number of what in the atom determines the element?

protons

What is an isotope?

same number of protons but different number of neutrons

Does an atom USUALLY have an equal number of electrons and protons?

yes

what is an ion?

has an unequal number of electrons and protons

what are the units of charge?

coulombs ©

The charge of an electron is

-1.6 × 10^-19c

The charge of a proton is

+1.6×10^-19

What does “charge is quantized” mean?

charge comes in discrete amounts

What is the smallest unit of charge in physics?

1/3e

What charge is an atom usually?

neutrally charged

Removing electrons gives what charge……

positive charge

Adding electrons gives what charge…..

negative charge

Do protons move?

no

What is a conductor?

a material where the elctrons can move freely about (metals, wires, water)

has lots of ions

What is an insulator?

a material where the electrons are not free to move

rubber, glass, air

What is a semi-conductor?

a special type of material that acts as both a conductor and insulator depending on the situation

can act like a switch letting electrons pass (conductor)

can block electrons from passing (insulator)

key to the information revolution

forces in decreasing order of strength

strong nuclear force

electromagnetic force

weak nuclear force

gravatational force

what is coulombs law?

describes force between two charged object

“The force between two charged objects is proportional to the product of the charges and inversely proportional to the square of the distance between the objects.”

opposite sign charges….

attract each other

Similar sign charges…

repel each other

a pair of forces is describes as

“attractive” or “repulsive”

electric force

use newtons

inversly proportional the the square of distance

measured from centers

proportional to the product of the two charges

very strong

attractive or repulsive

gravitational force

use newtons

inversely proportional to square of distance

measured from centers

proportional to product of the two masses

very weak

attractive only

unit for charge

culombs

ways to charge

rubbing

contact (conduction)

induction

polarization

contact/conduction

When a conducting object is charged (either negatively or positively), that charge can be shared with other conducting objects by touching the objects together

induction

Charging by induction does not require touching, but does require a source (or sink) for electrons to travel from (or to)

rubbing

one object will become positive

one object will become negative

ONLY ELECTRONS MOVE NEVER PROTONS

polar

partial charges

polarization

charges shifted slightly to one side

overall nuetral

positive on one side

negative on the other side