Electrostatic Charging Flashcards
electricity that does not move or is static
electrostatics
all electricity comes from ___ forces from atoms
electrical
positive ions
protons
negative ions
electrons
the accumulaton of ___ is where electricity comes from
electrons
neutral so there is equal number of protons and electrons
atoms
center of the atom is the ___
nucleus
nucleus is made up of ___ and ___
protons
nucleus
orbit around the nucleus
electrons
two types of electrical charges
positive charge
negative charge
___ is conserved; meaning it is neither created nor destroyed
charge
charge is also ___, that it occurs in discrete amounts
quantized
when you charge something by any method, no charges are created or destroyed
conservation of charge
which ion move from one atom to another?
electrons
three types of charging
charging by friction
charging by conduction
charging by induction
transfer of charge due to rubbing contact between materials
charging by friction
electrons are transferred from one object to another by touching
charging by conduction
electrons are grounded, which leaves a positive charge when a negative object is brought near
charging by induction
when you rub one material to another they are charged by ___
friction
the material losing ___ is positively charged
electron
the amount of gained and lost electrons is __ to each other
equal
production of electric charge on the surface of a conductor under the influence of an electric field
induction
the advantage of charging by ___ is that it can be repeated many times without any loss of charge from the inducing specimen like the negatively charged rod
induction
occurs when neutral objects are placed in contact with an already charged object
charging by conduction
if the object is -, ____ will push some of the excess electrons from the charged to the neutral object
electric repulsion
Touching a charged object to an uncharged object transfers some of the charge
contact charging
A charged object is brought close to an uncharged object
induction charging
This induces the electrons to move in the uncharged object.
polarization
If contact is then provided to the ground electrons will flow onto or off of the object.
grounding
In this case electrons would be attracted from the ground to the positive charge. If a negatively charged object had been brought close to the blue object, then electrons would be forced off of the blue object and would flow to the ground.
grounding
This produces an object that has the opposite charge of the original charge.
objects charged by induction
Rubbing two different materials together, a process known as
charging by friction
, is the simplest way to give something a charge.
charging by friction
Rub a piece of ebonite (very hard, black rubber) across a piece of animal fur. Explain
what happens.
The fur does not hold on to its electrons as strongly as the ebonite. At least some of the
electrons will be ripped off of the fur and stay on the ebonite. Now the fur has a slightly
positive charge (it lost some electrons) and the ebonite is slightly negative (it gained some
electrons).The net charge is still zero between the two… remember the conservation of charge.
No charges have been created or destroyed, just moved around
Rub a glass rod with a piece of silk. Explain what
happens.
This is the same sort of situation as the one above. In this case
the silk holds onto the electrons more strongly than the glass.
Electrons are ripped off of the glass and go on to the silk. The
glass is now positive and the silk is negativ
Rather than try to keep track of
all the combinations, we arrange
common materials in a chart
called an “
electrostatic series
tendency to hold on electrons materials
sulphur
brass
copper
ebonite
paraffin wax
silk
lead
fur
wool
glass
Whichever material is closer
to the top is holding
electrons tightly so it will have a ___charge.
negative
The material closer to the bottom has a greater chance of losing electrons, so it will be
___charged.
positively
just means that the two objects will come into actual
physical contact with each other
conduction
If the two objects are brought
close enough that an arc of
electricity jumps between them, it
counts as
conduction
We bring the two objects close together. We will see a ___of charge happen in the
neutral object as negative electrons are repelled to the right hand side
separation of charge
If the materials used were ___, only the specific areas that actually touched would show
any change in charge. That’s because the charges can’t move through the insulators easily.
insulators
It is possible to charge a conductor without touching it. You do have to follow some special procedures.
● Most important is the use of a ___wire
grounding
is simply a conductor that connects the object to the grounde
grounding wire
Very early on physicists started using ___to measure very small charges
on objects
electroscopes
is made up of a couple of very thin metal leaves that hang
down near to each other. They are connected to a metal rod that extends
upwards, and ends in a knob on the end.
electroscope
In this situation a negative
object is brought nearby the electroscope.
This causes free moving electrons in the
electroscope to move ___into the leaves,
leaving the top positive. Since the leaves
both have negative charge they repel each
other and move apart.
down
Bring a positive
object nearby and the free
electrons in the electroscope all
start moving up towards the
top. This means the bottom has
a net positive charge. The
leaves will spread ___ again.
apart
