Download negative charge - South Newcastle Trust

P2 Spaced Learning
All you need to do is
remember the red
highlighted words!
P2 Spaced Learning
All you need to do is
remember the red
highlighted words!
P2 Topic 1
Static and
electrical current
Number of protons
Mass Number
+
number of neutrons
X
Number of neutrons
Atomic Number (and equals the
number of electrons)
12 – So since 6 protons there
C6
must be 6 neutrons
– Protons = 6
& Electrons = 6
Make up
of an atom
Electron
Mass
1/2000
Charge
-1
Proton
Neutron
1
1
+1
0
As the number of protons equals the number of
electrons their charges cancel out to give atoms a
charge of zero.
Unless they are ionised. Ionised means that they have
gained or lost electrons.
In this atom there are 3 protons
and 3 electrons, this means that it
is electrically neutral;
+3 – 3 = 0
The same atom has lost 1 electron
so now it has 3 protons but 2
electrons it’s ionised;
+3 – 2 = +1
Note: It gains an equal but
opposite charge to what is lost
Charges are like magnets
Static electricity is the build up of electrostatic
charge in an insulating material. This is due to
the movement of electrons to or from the
insulating material due to friction.
Rubbing the rod with a
cloth moves electrons
from the cloth – the rod
becomes negatively
charged
Caused by Friction
Rubbing the rod with
a cloth moves
electrons to the cloth
– the rod becomes
positively charged
The charges in the wall are not completely free to
move as the wall is also an insulator and not a
conductor!
Note: The charges of the balloon will eventually
dissipate as they meet ions in the air
If charge builds up it can flow
to earth through a conductor
The conductor allows a
complete circuit to be made.
+
+
+
+
+ + + + + + + ++
- - As
cloudsofrub
Thethe
topside
the
past
Earth
cloudthe
becomes
electrons
positively(negative
charged
charge)
due builds
to the up
on
the underside
of
positively
charged
the cloud.
Earth
surface.
Sometimes insulators “break down” and conduct this needs a
large build up of charge, like lightning, where the negative
charge earths onto the positively charged Earth’s surface.
"Lightnings sequence 2 animation" by original data: Sebastien D'ARCO, animate: Koba-chan original source is Image:Lightnings sequence 2.jpg, animated by me.. Licensed under CC BY-SA
2.5 via Wikimedia Commons
When refuelling aircraft static electricity can build up both
on the aircraft itself and due to friction of the fuel through
the pipe.
SO
The aircraft, fuel tanker and pipe are earthed by a
conductor that allows the charge to flow safely to earth
(known as discharging) so that no charge is allowed to
build up. Remember lightning!!!
Negative charge given
to object being painted
Positive charge given
to paint
The positive paint droplets repel and spread out to
improve coverage. The negative charges on the object
attract the positive paint droplets so paint can cover all of
the object evenly.
Current is the flow of charge i.e. the flow of electrons. The
charge on an electron is so small that the unit of a
coulomb is used. 1 coulomb is the charge from
6,241,509,750,000,000,000 electrons !
Conventional Current Flow
Electron Flow
Current
(Amps, A)
Charge
(Coulombs, C)
𝑄
𝐼=
𝑡
Time
(seconds, s)
Direct Current or DC is where the supplied PD/Current remains fixed at
one value and in one direction, like from a battery.
Alternating Current or AC is where the supplied PD/Current vary
smoothly from one value and direction to another value and direction,
like from a plug socket.
Remember negative PD just means the charges are flowing in the
opposite direction.
These PDs can be shown on an oscilloscope like those above. Each
vertical square represents voltage each horizontal square represents
time.
What can
you
remember?
Number of protons
1
Mass Number
+
2
number of neutrons
X
Number of neutrons
Atomic Number (and equals the
3
number of electrons)
12 – So since 6 protons there
C6
must be 6 neutrons
– Protons = 6
& Electrons = 6
Make up
of an atom
Electron
Mass
1
1/2000
Charge
-1
Proton
Neutron
1
1
2
+1
0
3
As the number of protons
equals the number of
electrons their charges cancel out to give atoms a
charge of zero.
Unless they are ionised. Ionised means that they have
gained or lost
4 electrons.
In this atom there are 3 protons
and 3 electrons, this means that it
is electrically neutral;
2
1
+3 – 3 = 0
The same atom has lost 1 electron
so now it has 3 protons but 2
electrons it’s ionised;
+3 – 2 = +1
Note: It gains an equal but
opposite
3 charge to what is lost
Charges are like magnets
1
2
1
Static
electricity is the build up of electrostatic
charge
in an insulating
material. This is due to
2
3
the movement of electrons
to or from the
4
5
insulating material due to friction.
Rubbing the rod with a
cloth moves electrons
from the cloth – the rod
becomes negatively
charged
Caused by Friction
Rubbing the rod with
a cloth moves
electrons to the cloth
– the rod becomes
positively
6 charged
1
2
The charges in the wall are not completely free to
1
move as the wall is also an insulator
and not a
conductor!
Note: The charges of the balloon will eventually
dissipate as they meet ions in the air
1
If charge builds up it can flow
to earth through a conductor
The conductor allows a
1
complete
circuit to be made.
+
+
+
+
+ + + + + + + ++
- - As the clouds rub
4
past the Earth
electrons (negative
charge) builds up
on the underside of
the cloud.
The topside of the
cloud becomes
positively charged
due to the
5
positively
charged
Earth surface.
Sometimes insulators “break down” and conduct this needs a
2
1
large build up of charge,
like lightning,
where the negative
charge earths onto the positively
charged Earth’s surface.
3
When refuelling aircraft static electricity can build up both
on the aircraft itself and due to friction of the fuel through
the pipe.
SO
1
The aircraft, fuel tanker and pipe are earthed
by a
2
conductor
that allows the charge to flow safely to earth
3
(known as discharging)
so that no charge is allowed to
build up. Remember lightning!!!
Negative
charge given
1
to object being painted
Positive charge given
2
to paint
The positive paint droplets repel and spread out to
3
improve coverage.
The negative charges on the object
attract the positive paint droplets so paint can cover all of
4
the object evenly.
Current is the flow of1charge i.e. the flow of electrons. The
2
charge
on an electron is so small that the unit of a
coulomb
is used. 1 coulomb is the charge from
3
6,241,509,750,000,000,000 electrons !
Conventional Current Flow
Electron Flow
Current
4 A)
(Amps,
Charge
(Coulombs,
C)
5
𝑄
𝐼=
𝑡
Time
7
(seconds, s)
3
Direct1Current or DC is where the supplied PD/Current
remains fixed at
one value and in one direction, like from a battery.
2
Alternating Current or AC is where the supplied PD/Current vary
smoothly from one value and direction to another value and direction,
like from a plug socket.
4
Remember negative PD just means the charges are flowing in the
opposite direction.
These PDs can be shown on an oscilloscope like those above. Each
vertical5 square represents voltage each horizontal square represents
6
time.