Static Electricity Flashcards
(37 cards)
What is electricity
Electricity is the flow of electrical charges - it is the result of the movement of electrons.
It is the main form of energy used today.
NO NET CHARGE =
Matter with an equal number of protons and electrons.
Some energy sources used to make electricity are:
hydro dams
solar
coal
natural gas
wind
nuclear energy
Where does an electrical charge come from?
Each electron and each proton carries a tiny amount of electrical charge.
A net electrical charge comes from the imbalance of protons and electrons
Positive (+)
a positive charge occurs when there are more protons than electrons.
Negative (-)
a negative charge occurs when there are more electrons than protons.
Nucleons
The particles in the nucleus of atoms, protons and neutrons, are called nucleons.
Nucleons are what give an atom its identity (6P = carbon, 19P = K ,etc).
Nucleons are BIG when compared to electrons.
When it comes to electricity, nucleons DO NOT move.
Electrons
These particles are much smaller and lighter than nucleons
They are able to move from atom to atom in some materials.
They are responsible for the electrical phenomena we will be studying.
Measuring electrical charges
In lab experiments and everyday life, we cannot really notice and measure the effect of a single electron’s charge; it is too small (certain experiments can).
It is more common to measure the charge of large groups of displaced electrons. One coulomb contains many MANY electrons!
Charge of a proton
A proton has a positive charge of 1.60 x 10-19 C
Charge of an electron
Electrons have a negative charge of - 1.60 x 10-19 C
Unit
UNIT: coulomb ( C )
How many electrons are in 1 Coulomb?
Remember, one electron has a charge of (negative) 1.60 x 10-19 C.
x = 6.25 x 10 18 electrons
How much charge is contained in an object that has gained 3.2 x 1012 electrons?
Positive 3.52 x 10-5 C
How much charge is contained in an object that has lost 500 000 000 electrons?
negative 1.15 x 10-10 C
An object is found to have a net charge of -3.2 x 10-4 C. How many electrons were transferred IN or OUT of the object?
2 x 10 15
Electrical forces
When two charged objects come in close proximity to each other an electrical force is created.
If the objects are of opposite charge, the electrical force will pull them towards each other.
If the objects are of the same charge, the electrical force will push them apart.
TWO TYPES OF ELECTRICITY
static and dynamic
Static electricity
This is called static electricity because it is about stored, non-moving charges.
CHARGING OBJECTS
Most object are neutral (# of e- = # of p+)
For an object to become charged a transfer of e- must take place.
An object is deemed ”charged” when it has an unequal amount of positive and negative charges.
Objects can be positively or negatively charged. It is always via gaining or losing valence electrons that an object becomes charged.
FRICTION
Charging by rubbing (one material “likes” electrons more than another material and “takes” the electrons when they are rubbed)
CONDUCTION
Charging by contact (excess/deficit of electrons is shared between the objects in contact)
INDUCTION
Charging without contact (bringing a charged object close to another cause the uncharged object to become temporarily charged)
Friction procedure
Start with: two neutral objects made of different materials
One “likes” electrons more, and will take them from the
other object (See table)
Finish with: two oppositely charged objects
