Transcript Physics_2aandb_revision

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Physics 2
Madeley High School
Set 1 and 2 click here
for mock revision
Set 3, 4 and 5 click
here for mock revision
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Distance, Speed
and Time
D
Speed = distance (in metres)
time (in seconds)
S
T
1) Seb walks 200 metres in 40 seconds. What is his speed?
5 m/s
2) Lucy covers 2km in 1,000 seconds. What is her speed?
2 m/s
3) How long would it take Freddie to run 100 metres if he runs
at 10m/s?
10s
4) Sue travels at 50m/s for 20s. How far does he go?
1000m
5) Hannah drives her car at 85mph (about 40m/s). How long
does it take her to drive 20km?
500s = 8.3 mins
Distance-time graphs
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4) Diagonal line
downwards =
2) Horizontal line =
40
Stationary
Constant speed
opposite direction
30
Distance
(metres)
20
10
0
Time/s
20
1) Diagonal line =
Constant speed
40
60
80
100
3) Steeper diagonal line =
Higher constant speed
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40
Distance
(metres)
30
20
10
0
Time/s
20
40
60
80
1) What is the speed during the first 20 seconds?
100
0.5 m/s
2) How far is the object from the start after 60 seconds?
40 m
3) What is the speed during the last 40 seconds?
1 m/s
4) When was the object travelling the fastest? 40 to 60s
Speed vs. Velocity
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Speed is simply how fast you are travelling…
This car is travelling at a
speed of 20m/s
Velocity is “speed in a given direction”…
This car is travelling at a
velocity of 20m/s east
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Acceleration
v-u
Acceleration = change in velocity (in m/s)
(in m/s2)
time taken (in s)
a
T
1) A cyclist accelerates from 0 to 10m/s in 5 seconds. What
is her acceleration?
2m/s2
2) A ball is dropped and accelerates downwards at a rate of
10m/s2 for 12 seconds. How much will the ball’s velocity
increase by?
120 m/s
3) A car accelerates from 10 to 20m/s with an acceleration of
2m/s2. How long did this take?
5s
4) A rocket accelerates from 1,000m/s to 5,000m/s in 2
seconds. What is its acceleration? 2000 m/s2
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Velocity-time graphs
1) Upwards line =
Accelerating
80
Velocity
m/s
4) Downward line =
decelerating
60
40
20
0
10
2) Horizontal line =
Constant speed
20
30
40
50
3) Upwards line =
Slower acceleration
T/s
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80
60
Velocity
m/s
40
c) 0.5x10x20 =
100
20
a) 0.5 x 10 x 40
0
= 200
b) 20 x 40 =
800
10
20
d) 0.5 x 20 x 60
= 600
30
40
1) How fast was the object going after 10 seconds?
2) What is the acceleration from 20 to 30 seconds?
3) What was the deceleration from 30 to 50s?
4) How far did the object travel altogether?
T/s
50
40 m/s
2 m/s2
3 m/s2
200+800+100+600=
1700 m
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Balanced and unbalanced forces
Consider a camel standing on a road.
What forces are acting on it?
Reaction
These two forces would be equal –
we say that they are BALANCED.
The camel doesn’t move anywhere.
Weight
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Balanced and unbalanced forces
Reaction
What would happen if we took the
road away?
Weight
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Balanced and unbalanced forces
What would happen if we took the
road away?
The camel’s weight is no longer
balanced by anything, so the camel
falls downwards…
Weight
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Balanced and unbalanced forces
What would happen if we took the
road away?
The camel’s weight is no longer
balanced by anything, so the camel
falls downwards…
Air Resistance
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Air resistance is a force that opposes motion through air. The
quicker you travel, the bigger the air resistance:
The same applies to a body falling through a liquid (called
“drag” or “upthrust”).
Balanced and unbalanced forces
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Accelerating
Accelerating
Steady speed
Decelerating
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Balanced and unbalanced forces
1) This animal is either
Stationary
________ or moving
with Steady
_____ speed
_____…
3) This animal is getting
slower
_______….
2) This animal is getting
faster
_________…
4) This animal is…
stationary
Resultant Force
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Calculate the resultant force of the following:
500N
100N
700N
600N
100 N
400 N
50N
200 N
700N
700N
200N
800N
100N
800N
50 N
Force and acceleration
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If the forces acting on an object
are unbalanced then the object will
accelerate, like these wrestlers:
Force (in N) = Mass (in kg) x Acceleration (in m/s2)
F
M
A
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Force, mass and acceleration
1) A force of 1000N is applied to push
a mass of 500kg. How quickly does
it accelerate? 2m/s2
F
2) A force of 3000N acts on a car to
make it accelerate by 1.5m/s2. How
heavy is the car? 2000 kg
3) A car accelerates at a rate of
5m/s2. If it weighs 500kg how
much driving force is the engine
applying?
2500 N
m
4) A force of 10N is applied by a boy
while lifting a 20kg mass. How
much does it accelerate by? 0.5 m/s2
a
Terminal Velocity
Consider a skydiver:
1) At the start of his jump the air
small so he
resistance is _______
accelerates
_______ downwards.
2) As his speed increases his air
resistance will increase
_______
3) Eventually the air resistance will be
balance the
big enough to _______
skydiver’s weight. At this point
the forces are balanced so his
speed becomes constant
________ - this is
called TERMINAL VELOCITY
Words – increase, small,
constant, balance, accelerates
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Terminal Velocity
Consider a skydiver:
4) When he opens his parachute the
increases
air resistance suddenly ________,
Slowing____.
down
causing him to start _____
5) Because he is slowing down his air
decrease again until
resistance will _______
weight
it balances his _________.
The
skydiver has now reached a new,
lower ________
Terminal _______.
velocity
Words – slowing down, decrease,
increases, terminal velocity, weight
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Velocity-time graph for terminal velocity…
Parachute opens –
diver slows down
Velocity
Speed
increases…
Terminal
velocity
reached…
Time
New, lower terminal
velocity reached
Diver hits the ground
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Weight vs. Mass
Earth’s Gravitational Field Strength is 10N/kg. In other
words, a 1kg mass is pulled downwards by a force of 10N.
W
Weight = Mass x Gravitational Field Strength
(in N)
(in kg)
(in N/kg)
M
1) What is the weight on Earth of a book with mass 2kg?
2) What is the weight on Earth of an apple with mass 100g?
g
20 N
1N
3) Dave weighs 700N. What is his mass? 70 kg
4) On the moon the gravitational field strength is 1.6N/kg. What will
Dave weigh if he stands on the moon? 112 N
Stopping a car…
Tiredness
Thinking
distance
Too many
drugs
(reaction time)
Icy roads
Tyres/brakes
worn out
Braking
distance
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Too much
alcohol
Caffeine
Driving too
fast
Wet roads
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Work done
When any object is moved around work will need to be
done on it to get it to move (obviously).
We can work out the amount of work done in moving an
object using the formula:
Work done = Force x distance moved
in J
in N
W
in m
F
D
Example questions
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1. Bori pushes a book 5m along the table with a force of 5N.
He gets tired and decides to call it a day. How much work
did he do?
25 J
2. Alicia lifts a laptop 2m into the air with a force of 10N.
How much work does she do? 20 J
3. Martin does 200J of work by pushing a wheelbarrow with a
force of 50N. How far did he push it? 4 m
4. Chris cuddles his cat and lifts it 1.5m in the air. If he did
75J of work how much force did he use? 50 N
5. Carl drives his car 1000m. If the engine was producing a
driving force of 2000N how much work did the car do?
2,000,000 J
Elastic Potential Energy
Elastic potential energy is the
energy stored in a system
when work is done to change
its shape, e.g:
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Kinetic energy
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Any object that moves will have kinetic energy.
The amount of kinetic energy an object has can be found using
the formula:
Kinetic energy = ½ x mass x velocity squared
in J
in kg
KE =
½
in m/s
mv2
Example questions
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1) Nicole drives her car at a speed of 30m/s. If the
combined mass of her and the car is 1000kg what is her
kinetic energy? 450,000 J
2) Shanie rides her bike at a speed of 10m/s. If the
combined mass of Shanie and her bike is 80kg what is her
kinetic energy?
4,000 J
3) Dan is running and has a kinetic energy of 750J. If his
mass is 60kg how fast is he running?
5 m/s
4) George is walking to town. If he has a kinetic energy of
150J and he’s walking at a pace of 2m/s what is his mass?
75 kg
Random questions…
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1) Sophie tries to run 100m in 12 seconds and succeeds. How fast did she
run?
8.3 m/s
2) Tommy accelerates at a rate of 2m/s2 for 3 seconds. If he started at
10m/s what was his final speed? 16 m/s
3) Charlie decides to lift his book up into the air. His book has a mass of
100g and he lifts it 50cm. Calculate the work done. 0.05 J
4) Lewis accelerates from 0 to 10m/s in 5 seconds. If his mass is 70kg
how much force did his legs apply? 140 N
50s
5) Rachel rides 1km at a speed of 20m/s. How long did the journey take?
6) Claire thinks it’s funny to push James with a force of 120N. If James
has a mass of 60kg calculate his acceleration.
2 m/s2
7) Lauren slams on the brakes on her bike and her brakes do 20,000J of
work. If the combined mass is 100kg what speed was she travelling at?
20 m/s
8) Tom has a mass of 75kg. If he accelerates from 10 to 20m/s in 2s how
much force did he apply?
375 N
Random questions…
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9) Georgina amuses herself by throwing things at Sarah. If she throws a
ball with a speed of 20m/s and the distance between her and Sarah is
5m how long will it take to reach her? 0.25 s
10) Mr Royall throws calculators around the room with a force of 2N. If
each calculator has a mass of 200g calculate the acceleration.
10m/s2
11) Sam has a mass of 70kg. What is his weight on Earth, where the
gravitational field strength is 10N/kg?
700 N
12) Zak does some work by pushing a box around with a force of 1N. He
does 5J of work and decides to call it a day. How far did he push it?
5m
13) On the moon Matt might weigh 112N. If the gravitational field
strength on the moon is 1.6N/kg what is his mass? What will he weigh
on Earth?
70 kg, 700N
14) Dan likes bird watching. He sees a bird fly 100m in 20s. How fast was
it flying?
5 m/s
15) How much kinetic energy would Richard have if he travelled at a speed
of 5m/s and has a mass of 70kg?
875 J
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Momentum
Any object that has both mass and
velocity has MOMENTUM. Momentum
(symbol “p”) is simply given by the formula:
P
Momentum = Mass x Velocity
(in kgm/s)
(in kg)
(in m/s)
M
V
What is the momentum of the following?
1) A 1kg football travelling at 10m/s
10 kgm/s
2) A 1000kg Ford Capri travelling at 30m/s 30,000 kgm/s
3) A 20g pen being thrown across the room at 5m/s 0.1 kgm/s
4) A 70kg bungey jumper falling at 40m/s 2800 kgm/s
Conservation of Momentum
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In any collision or explosion momentum is conserved (provided that there
are no external forces have an effect). Example question:
Two cars are racing around the M25. Car A collides with the back of car B
and the cars stick together. What speed do they move at after the
collision?
Speed = 50ms-1
Mass = 1000kg
Speed = 20ms-1
Mass = 800kg
Mass = 1800kg
Speed = ??ms-1
Momentum before = momentum after…
…so 1000 x 50 + 800 x 20 = 1800 x V…
…V = 36.7ms-1
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Momentum in different directions
What happens if the bodies are moving in opposite directions?
Speed = 50ms-1
Mass = 1000kg
Speed = 20ms-1
Mass = 800kg
Momentum is a VECTOR quantity, so the momentum of the
second car is negative…
Total momentum = 1000 x 50 – 800 x 20 = 34000 kgms-1
Speed after collision = 34000 kgms-1 / 1800 = 18.9ms-1
More questions…
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1) A white snooker ball moving at 5m/s strikes a red ball and pots it.
Both balls have a mass of 1kg. If the white ball continued in the same
direction at 2m/s what was the velocity of the red ball?
3 m/s
2) A car of mass 1000kg heading up the M1 at 50m/s collides with a
stationary truck of mass 8000kg and sticks to it. What velocity does
the wreckage move forward at?
5.5 m/s
3) A defender running away from a goalkeeper at 5m/s is hit in the back
of his head by the goal kick. The ball stops dead and the player’s speed
increases to 5.5m/s. If the ball had a mass of 500g and the player had
a mass of 70kg how fast was the ball moving?
70 m/s
4) A gun has a recoil speed of 2m/s when firing. If the gun has a mass of
2kg and the bullet has a mass of 10g what speed does the bullet come
out at?
400 m/s
Safety features
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Basically:
1) The change in momentum is the same with or without an
airbag
2) But having an airbag increases the time of the collision
3) Therefore the force is reduced
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Static Electricity
Static electricity is when charge “builds up” on an insulating
object and then stays “static”. How the charge builds up
depends on what materials are used:
-
+
-
+
-
+
+
-
-
+
-
+
-
+
-
+
Only the electrons can move!
+
-
-
+
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Static Electricity
+
+
-
+
-
-
Opposite charges attract
-
-
-
-
-
Like charges repel
-
Circuit Symbols
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Variable
resistor
Diode
Switch
Bulb
A
V
Ammeter
Voltmeter
LDR
Resistor
Cell
Fuse
Thermistor
Battery
Electric Current
Electric current is a flow
of negatively charged
particles (i.e. electrons).
+
-
e-
Note that
electrons go
from negative
to positive
By definition, current is “the
rate of flow of charge”
e-
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Basic ideas…
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Electric current is when electrons start to flow around a
ammeter to measure it and it is
circuit. We use an _________
amps
measured in ____.
Potential difference (also called _______)
voltage is
how big the push on the electrons is. We use a
voltmeter to measure it and it is measured in
________
volts a unit named after Volta.
______,
Resistance is anything that resists an electric current. It is
ohms
measured in _____.
Words: volts, amps, ohms, voltage, ammeter, voltmeter
More basic ideas…
If a battery is
added the current
increase
will ________
because there is a
push on
greater _____
the electrons
If a bulb is added
the current will
decrease because
_______
there is greater
resistance in the
________
circuit
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Current in a series circuit
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If the current
here is 2
amps…
The
current
here will
be…
The current
here will
be…
And the
current
here will
be…
In other words, the current in a series
circuit is THE SAME at any point
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Current in a parallel circuit
A PARALLEL circuit is one where the current has a “choice
of routes”
Here comes the current…
Half of the current
will go down here
(assuming the bulbs
are the same)…
And the rest will
go down here…
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Current in a parallel circuit
If the
current
here is 6
amps
And the
current here
will be…
6 amps
The current
here will be…
2 amps
The current
here will be…
2 amps
The current
here will be…
2 amps
Some example questions…
Circuit 1
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6A
3A
1A
1A
1A
Circuit 2
4A
2A
1) In circuit 1, if the bulbs are identical,
what will the current through each be?
2) In circuit 2, one branch has 4A through
it. Which one and what will the other
one be?
Voltage in a series circuit
If the voltage
across the
battery is 6V…
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V
…and these
bulbs are all
identical…
…what will the
voltage across
each bulb be?
V
V
2V
Voltage in a series circuit
If the voltage
across the
battery is 6V…
…what will the
voltage across
two bulbs be?
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V
V
4V
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Voltage in a parallel circuit
If the voltage across
the batteries is 4V…
What is the
voltage here?
4V
V
And here?
V
4V
Summary
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In a SERIES circuit:
Current is THE SAME at any point
Voltage SPLITS UP over each component
In a PARALLEL circuit:
Current SPLITS UP down each “strand”
Voltage is THE SAME across each”strand”
An example question:
3A
6V
A3
3A
A1
V1
3V
6V
A2
V2
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1A
2A
3V
V3
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Resistance
Resistance is anything that will
RESIST a current. It is measured
in Ohms, a unit named after me.
Georg Simon Ohm
1789-1854
The resistance of a component can be
calculated using Ohm’s Law:
Resistance
(in )
=
V
Voltage (in V)
Current (in A)
I
R
An example question:
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Ammeter
reads 2A
A
V
Voltmeter
reads 10V
1) What is the resistance across
this bulb?
2) Assuming all the bulbs are the
same what is the total resistance
in this circuit?
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More examples…
3A
6V
12V
2 
3A
2A
4V
2V
1A
What is the
resistance of
these bulbs?
Resistance
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Resistance is anything that opposes an electric current.
Resistance (Ohms, ) =
Potential Difference (volts, V)
Current (amps, A)
What is the resistance of the following:
1) A bulb with a voltage of 3V and a current of 1A.
2) A resistor with a voltage of 12V and a current of 3A
3) A diode with a voltage of 240V and a current of 40A
4) A thermistor with a current of 0.5A and a voltage of
10V
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Resistors, bulbs and diodes
Current-Voltage Graphs
Voltage on
powerpack/V
12
10
…
0
…
-10
-12
Current/A
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Voltage/V
Get the graphs from measuring
the current and voltage across
the component in an experiment.
Plot current along the x axis and
voltage up the axis – the
components have distinctive
shapes that you need to be able to
identify and describe
Current-voltage graphs
I
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I
I
V
V
V
1. Resistor
Current
increases in
proportion
to voltage
2. Bulb
As voltage increases
the bulb gets hotter
and resistance
increases
3. Diode
A diode only lets
current go in one
direction – it has
very high
resistance in the
other direction
LDRs and Thermistors
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Two simple components:
1) Light dependant
resistor – resistance
DECREASES when light
intensity INCREASES
Resistance
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2) Thermistor –
resistance DECREASES
when temperature
INCREASES
Resistance
Amount of light
Temperature
Wiring a plug
1. Earth
wire
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4. Live
wire
5. Fuse
2. Neutral
wire
3. Insulation
The neutral wire of a plug stays at
a potential close to zero relative
to the Earth
6. Cable
grip
The live wire of a plug alternates
between positive and negative
potential relative to the Earth
DC and AC
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V
DC stands for “Direct
Current” – the current only
flows in one direction:
Time
1/50th s
AC stands for “Alternating
Current” – the current
changes direction 50 times
every second (frequency =
50Hz)
230V
T
V
Using an oscilloscope
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Q. What is the voltage and
frequency of this supply?
10
3 sq,
sq,
Frequency:
period == 5
Voltage:
amplitude
4
sq,
1V. Period
Voltage= =10s.
20s.
3V
each sq = 2s.
4V
Frequency = 1/period
= 1/20
1/10 = 0.05Hz
0.1 Hz
This number tells
you how many
volts each square
on the vertical
axis represents
This number tells
you how many
seconds each square
on the horizontal
axis represents
Fuses
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Safety devices. If
Fuses are _______
there is a fault in an appliance
live and neutral
which causes the ____
(or earth) wire to cross then a
large current will flow through
______
melt
the fuse
_____ and cause it to _____.
circuit and
This will break the _______
protect the appliance and user
harm
from further _____.
Words – large, harm, safety, melt, live, circuit, fuse
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Power and fuses
Power is “the rate of doing work”.
The amount of power being used in
an electrical circuit is given by:
Power = voltage x current
in W
in V
in A
P
V
I
Using this equation we can work out the fuse rating for any
appliance. For example, a 3kW (3000W) fire plugged into a
12.5
240V supply would need a current of _______
A, so a
13
_______
amp fuse would be used (fuse values are usually 3,
5 or 13A).
Power and fuses
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Copy and complete the following table:
Appliance
Power rating
(W)
Voltage (V)
Current
needed (A)
Fuse needed
(3, 5 or 13A)
Toaster
960
240
4
5
Fire
2000
240
8.3
13
Hairdryer
300
240
1.25
3
Hoover
1000
240
4.2
5
Computer
100
240
0.4
3
Stereo
80
240
0.3
3
Energy and Power
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The POWER RATING of an appliance is simply how much
energy it uses every second.
In other words, 1 Watt = 1 Joule per second
E
E = Energy (in joules)
P = Power (in watts)
T = Time (in seconds)
P
T
Some example questions
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1) What is the power rating of a light bulb that transfers 120
joules of energy in 2 seconds? 60W
2) What is the power of an electric fire that transfers
10,000J of energy in 5 seconds? 2,000W
3) Farhun runs up the stairs in 5 seconds. If he transfers
1,000,000J of energy in this time what is his power rating?
200,000W
4) How much energy does a 150W light bulb transfer in a) one
second, b) one minute? a) 150W b) 9,000W
5) Shaun’s brain needs energy supplied to it at a rate of 40W.
How much energy does it need during a physics lesson?
144,000J
6) Damien’s brain, being more intelligent, only needs energy at
a rate of about 20W. How much energy would his brain use
in a normal day? 1,728,000J
Earth wires
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metal
Earth wires are always used if an appliance has a _____
fault in the appliance, causing the live
case. If there is a _____
touch the case, the current “_______”
surges
wire to ______
down the
fuse blows.
earth wire and the ______
Words – fuse, fault, metal, surges, touch
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Charge (Q)
As we said, electricity is when electrons move around a
circuit and carry energy with them. Each electron has a
negative CHARGE. Charge is measured in Coulombs (C).
We can work out how much charge flows in a circuit using
the equation:
Charge = current x time
(in C)
(in A)
Q
(in s)
I
T
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Example questions
Charge (C)
Current (A)
Time (s)
5
2
0.4
1
20
0.5
0.4
40
50
0.2
10
180
250
3
60
1) A circuit is switched on for 30s with a current of 3A. How much
charge flowed?
90C
2) During electrolysis 6A was passed through some copper chloride
and a charge of 1200C flowed. How long was the experiment on
for? 200 s
3) A bed lamp is switched on for 10 minutes. It works on a current of
0.5A. How much charge flowed?
300 C
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Energy and charge
The amount of energy that flows in a circuit will depend on
the amount of charge carried by the electrons and the
voltage pushing the charge around:
Energy transferred = charge x voltage
(in J)
(in C)
(in V)
E
V
Q
Example questions
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1) In a radio circuit a voltage of 6V is applied and a charge
of 100C flows. How much energy has been transferred?
600J
2) In this circuit the radio drew a current of 0.5A. How
long was it on for?
200s
3) A motor operates at 6V and draws a current of 3A. The
motor is used for 5 minutes. Calculate: a) The motor’s
resistance, b) the charge flowing through it, c) the
energy supplied to it
a) 2 Ω b) 900C c) 5400J
4) A lamp is attached to a 12V circuit and a charge of
1200C flows through it. If the lamp is on for 10 minutes
calculate a) the current, b) the resistance, c) the energy
supplied to the bulb.
a) 2A
b) 6 Ω
c) 14,400J
Random questions
26/03/2016
1) A battery has a voltage of 12V and it puts a current of 3A
through a bulb. What is the bulb’s resistance? 4 Ω
2) Another bulb transfers 120C of charge in 2 minutes. What
was the current through it?
1A
3) A powerpack transfers 2,000J to a motor. If the motor
ran on a voltage of 50V how much charge was transferred?
40 C
4) A hairdryer runs on a 50Hz power supply. If it has a power
rating of 200W what fuse should it have?
3A
5) An electric fire transfers 3MJ of energy. If it has a
power rating of 2KW calculate a) the current it ran on
(assuming it was connected to the mains supply), b) the
amount of charge it transferred and c) how long it was on
for,
c) 1500 s
a) 8.7A
b) 13043.5 C
Structure of the atom
A hundred years ago people thought
that the atom looked like a “plum
pudding” – a sphere of positive
charge with negatively charged
electrons spread through it…
Ernest Rutherford, British scientist:
I did an experiment (with my colleagues
Geiger and Marsden) that proved this
idea was wrong. I called it the
“Scattering Experiment”
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The Rutherford Scattering Experiment
Alpha
particles
(positive
charge, part
of helium
atom)
Most particles passed
through, 1/8000 were
deflected by more than
900
Conclusion – atom is made up of a small, positively
charged nucleus surrounded by electrons orbiting
in a “cloud”.
Thin gold
foil
The structure of the atom
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ELECTRON –
negative, mass
nearly nothing
NEUTRON –
neutral, same
mass as
proton (“1”)
PROTON –
positive, same
mass as
neutron (“1”)
The structure of the atom
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Particle
Proton
Relative Mass
1
Relative Charge
+1
Neutron
Electron
1
0
0
-1
MASS NUMBER = number of
protons + number of neutrons
SYMBOL
PROTON NUMBER = number of
protons (obviously)
Isotopes
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An isotope is an atom with a different number of neutrons:
Notice that the mass number is different. How many
neutrons does each isotope have?
Each isotope has 8 protons – if it didn’t then it just
wouldn’t be oxygen any more.
A “radioisotope” is simply an isotope that is radioactive –
e.g. carbon 14, which is used in carbon dating.
Background Radiation
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13% are
man-made
Radon gas
Food
Cosmic rays
Gamma rays
Medical
Nuclear power
Types of radiation
Unstable
nucleus
New
nucleus
Alpha
particle
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1) Alpha () – an atom decays into a new
atom and emits an alpha particle (2
protons and 2neutrons
______ – the nucleus of a
helium atom)
______
2) Beta () – an atom decays into a new
atom by changing a neutron into a
proton and electron. The fast moving,
_______
beta
Beta high energy electron is called a _____
particle particle.
Unstable
nucleus
New
nucleus
Unstable
nucleus
New
nucleus
3) Gamma – after  or  decay surplus
energy is sometimes emitted. This is
______
called gamma radiation and has a very
high frequency
________ with short wavelength.
The atom is not changed.
Gamma
radiation
Words – frequency, proton,
energy, neutrons, helium, beta
Nuclear fission
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More
neutrons
Neutron
Uranium or
plutonium
nucleus
Unstable
nucleus
New nuclei
(e.g. barium
and krypton)
Chain reactions
Each fission reaction releases
neutrons that are used in
further reactions.
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Nuclear Fusion in stars
Proton
Neutron
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