Whole Course Flashcards
1
Q
Describe how a cyclist can streamline themself
A
- Crouch over the handlebars
- Wear tight lycra clothing
- Specially shaped helmet
2
Q
What is meant by capacitance?
A
Charge stored per unit volt
3
Q
An astronaut has a mass of 50kg. What will happen to the astronauts weight on the Moon?
A
The weight will decrease as there is a lower gravitaional field strength on the Moon.
4
Q
Explain how a fusion reactor could generate electrical energy.
A
- At high temperature and pressure small nuclei join together
- This releases huge amounts of heat energy (Nuclear to Heat)
- The heat energy is used to heat water to steam.
- The steam is used to turn a turbine. (Heat to Kinetic)
- The turbine is used to turn a generator. (Kinetic to Electrical)
5
Q
What is the energy change in a battery?
A
Chemical to electrical
6
Q
Which circuit component is represented by the following diagram?
A
MOSFET
7
Q
What is an asteroid?
A
An asteroid is a small rocky and airless object that orbit the sun. They are too small to be planets.
8
Q
What will absorb beta radiation?
A
A few millimetres of aluminium
9
Q
How can you tell from this oscilloscope image that this is AC?
A
The trace shows a change in direction
10
Q
What are the issues of pressure differential?
A
Pressure in space is so low it is almost zero. Space suits and pressurised space craft are required to protect astronauts otherwise they would lose conciousness and suffocate or their blood could boil.
11
Q
What happens if light is shone onto a surface at an angle greater than the critical angle?
A
It is no longer refracted it is totally internally reflected.
12
Q
What happens to a light ray as it travels from water into air?
A
It speeds up and changes direction away from the normal.
13
Q
What does the path a projectile takes look like?
A
Curve
14
Q
What is the difference between mass and weight?
A
Mass is a measure of the partcles that make an object up. Weight is a force caused by the gravitational field strength of a planet.
15
Q
What is the rule for voltages in a parallel circuit?
A
The voltage across each branch is equal to the supply voltage.
16
Q
Why is maintaining energy such a big issue in space exploration?
A
Energy is required to maintain life support systems. It would be difficult to carry enough fuel so energy must be generated in space.
17
Q
Name one source of AC
A
Mains supply
18
Q
What is speed?
A
Distance travelled per second.
19
Q
How should a diode or LED be connected with a battery to light correctly?
A
Small line on battery points to small line on LED or diode.
20
Q
What is conservation of energy?
A
Energy cannot be created or destroyed it can only be transferred from one type to another.
21
Q
What is the charge on an electron?
A
Negative
22
Q
State one source of visible light.
A
- The Sun
- Light bulbs
- Anything hot enough to glow
23
Q
What would the field lines around a positive point charge look like?
A
Field lines show direction away from the positive point charge.
24
Q
Which component does the symbol represent?
A
Buzzer
25
What will be the voltage across a capacitor when it is fully discharged?
Zero volts.
26
What is a fuse?
Safety device that protects the flex
27
What is the difference in the diffraction pattern in a long wavelength and a short wavelength passing an object?
The longer wavelength diffracts more.
28
What is the symbol for an ammeter?
Circle with an A in it.
29
State one detector of gamma radiation
* Photographic film
* GM Tube
* Bubble chamber
30
Which circuit component is represented by the following diagram?
Transistor
31
What is the 'observable universe'?
**The observable** **universe** is the furthest point that we can ‘see’ or detect.
32
What is a galaxy?
A galaxy is a gravitationally bound system of stars, stellar remnants, gas, dust and dark matter.
33
What is meant by the half-life of a source?
It is the length of time it takes for the activity of a source to drop to half of it's original value.
34
What is the radiation known as alpha particles?
It is a helium nucleus.
(It has 2 protons and 2 neutrons.)
35
How can you identify a series circuit?
It is a circuit with only one path round it.
36
What is the energy chage in a battery?
Chemical to electrical
37
What are the three effects a force can have?
* Change the speed of the object
* Change the direction of travel of the object
* Change the shape of the object
38
State one use for gamma radiation.
* Used as a tracer in medicine
* Used to treat cancer
* Sterilisation of operating instruments
* In industry, radioactive "tracer" substances can be put into pipes and machinery, then we can detect where the substances go.
* Gamma rays kill microbes, and are used to so that it will keep fresh for longer. This is known as "irradiated" food.
* Checking for cracks in aeroplane wings and joints
39
If an object is projected horizontally or dropped, how can the vertical velocity just before it hits the ground be calculated?
Use a=(v-u)/t
u is 0ms-1
a is 9.8ms-2
v you are calculating
t is the time it falls for
a = (v-0)/t
v = at
40
An astronaut has a mass of 50kg. What will happen to the astronauts mass on the Moon?
It stays at 50kg. Mass does not change.
41
What is meant by equivalent dose rate?
Equivalent dose absorbed per unit time.
42
What is meant by the Big Bang?
It suggests that all the matter in the universe was in an infinitely small, hot and dense state which then expanded.
43
Will long or short wavelengths diffract more?
Lomg wavelengths diffract more.
44
How is a uniform electric field represented?
Evenly spaced field lines
45
What is a moon?
A natural satellite
46
Why is an LED normally connected in series with a resistor?
Resistor is to protect the LED by limiting the current in the LED.
47
What is a thermistor?
A resistor whose resistance changes with changes in temperature
48
Which circuit component is represented by the following diagram?
Loudspeaker
49
What is work?
It is the measure of the energy used to move an object over a distance using a force.
50
What is the link between the radiation weighting factor and the ionisation caused by a source?
The more ionisation the higher the radiation weighting factor.
51
State two place a variable resistor can be used.
Light dimmer switch sped control on Scalextric cars volume control on a radio
52
Which circuit component is represented by the following diagram?
Resistor
53
What happens if you increase the resistance in a circuit?
The current will decrease
54
What type of wave is a sound wave?
Longitudinal.
55
What is the symbol for an Ohmmeter?
Circle with an Omega in it
56
Name one source of AC
Mains supply
57
What is the charge on a gamma ray?
No charge
58
Why is travelling large distance in space such an issue?
Carrying the fuel required would be impossible.
59
What is the radiation known as gamma radiation?
It is a wave and part of the electromagnetic spectrum.
60
Explain how to measure the acceleration of the car using the equipment shown below and a stop watch.
* Car starts from rest so u = 0ms-1.
* When the car is released start the stop watch when it reaches the light gate stop the stop watch.
* This is t, the time for the change in velocity.
* When the cardboard passes through the light gate the timer attached to it records this time.
* Measure the length of the card with a ruler.
* The final velocity, v = length of card / time on timer
* Then calculate acceleration, a = (v-u)/t
61
What is the charge on a proton?
Positive
62
Should the engine force or the resultant force be used when calculating the acceleration of a space rocket on take off?
Resultant force
63
Name three vector quantities
* Displacement
* Velocity
* Acceleration
* Force
* Momentum
* Weight
64
What is meant by gravitational field strength?
Force per unit mass
65
Which line on the graph represents the corrected count rate? Give a reason for your answer.
It is the dotted red line.
You know this is the corrected reading as it is lower than the other reading as background has been subtracted.
This graph gives a 0 reading for the count rate, this is not possible as there is always background radiation so must be the corrected graph.
66
Which circuit component is represented by the following diagram?
Thermistor
67
What is the radiation weighting factor?
A number that takes into account the type of radiation you are exposed to.
68
How should a voltmeter be connected to measure the voltage across a component?
It should be connected across the component
69
What is meant by the potential difference (voltage) of a supply?
It is the number of Joules of energy given to each coulomb of charge passing through the cell
70
What is the energy change in a lamp?
Electrical to light (+ heat)
71
How does a relay work?
* Close a switch to make a current flow in a wire.
* This creates an electromagnet.
* Electromagnet attracts metal switch.
* This completes the second circuit and the lamp switches on.
72
What happens to the object at point X?
It changes direction
73
What is the weight of an object in freefall?
0 Newtons
74
What effect is shown here?
Diffraction
75
Which circuit component is represented by the following diagram?
Diode
76
What is latent heat of vaporisation?
The number of Joules of energy required to change 1kg of a liquid to 1kg of a gas with no temperature change.
77
Name a longitudinal wave.
Sound.
78
State one use for X-rays.
* Create images of bones to detect breaks
* Create images of organs for diagnosis
* Security to scan luggage at airports
* Doctors can give patients a “Barium Meal", which is a drink of Barium Sulphate. This will absorb X-rays, and so the patient's intestines will show up clearly on a X-Ray image.
79
What type of current is represented by this oscilloscope image?
AC
80
A temperature - time graph is shown below. What is happening at point E on the graph?
The temperature of the gas is increasing.
81
Explain how to use the equipment below to calculate the instantaneous speed of the car.
* Measure the length of the cardboard using a ruler.
* Roll car down the slope.
* When the cardboard breaks the beam it starts the timer connected to the light gate. When the cardboard has passed through the beam is remade and the timer stops.
* Speed = length of cardboard / time on timer
82
What would the field lines look between parallel plates?
Field lines run from positive to negative plate, with a bulge at the ends of the parallel plate.
83
How can you indicate a stronger electric field?
More field lines
84
What will absorb alpha radiation?
A few centimetres of air or a sheet of paper.
85
Which circuit component is represented by the following diagram?
Loudspeaker
86
Explain why the angle of re-entry poses a challenge.
The angle of re-entry to the atmosphere is important
* too steep and the change in kinetic energy being transferred to heat is too fast resulting in overheating and possible rocket break-up
* If the angle is too shallow you will skip off the atmosphere.
87
What is power?
The energy used per second
88
Which circuit component is represented by the following diagram?
MOSFET
89
Which circuit component is represented by the following diagram?
Capacitor
90
What will be the voltage across a capacitor when it is fully discharged?
Zero volts.
91
What is the annual effective dose of the average annual background radiation in the UK?
2.2mSv
92
What is meant by the activity of a source?
It is the number of decays/disintegrations per second
93
What is meant by gravitational field strength?
Force per unit mass
94
What is the charge on a proton?
Positive
95
Which device measures current?
Ammeter
96
State a device that can be used in a light sensor
LDR
97
State 2 issues that must be overcome in fusion reactors.
1. The high temperatures required
2. The high pressures required
98
How can you work out the resultant force acting on a space rocket at launch?
Resultant force = Engine thrust - (Weight + frictional forces)
99
What is DC?
Direct current. Electrons move in one direction only.
100
What is the symbol for a voltmeter?
Circle with a V in it
101
For a projectile fired horizontally, what would the horizontal velocity time graph look like?
Constant horizontal velocity - therefore a straight horizontal line.
102
What effect does a convex lens have on light rays?
The light rays converge to a focal point, by refraction of the light.
103
Explain how a seatbelt works in terms of Newton's Laws.
* When a car travels at a constant velocity the forces on it are balanced. (Newtons 1st Law)
* If the brakes are applied they provide an unbalanced force that stops the car. (Newtons 2nd Law)
* The passengers continue to travel at a constant speed in a straight line. (Newtons 1st Law)
* The seatbelt provides an unbalanced backwards force to decelerate the passenger to zero without hitting the windscreen. (Newtons 2nd Law)
104
What is the fuel in a nuclear fission reactor?
Uranium
105
State one detector of visible light.
* Retina in the eye,
* photographic film
106
A car is travelling at a constant velocity of 25ms-1, the engine is producing a force of 4000N. What is the size of the frictional forces acting on the car?
4000N backwards
107
What is the rule for current in a series circuit?
The current is the same everywhere
108
How does a relay work?
* Close a switch to make a current flow in a wire.
* This creates an electromagnet.
* Electromagnet attracts metal switch.
* This completes the second circuit and the lamp switches on.
109
Describe an experiment to investigate the relationship between the temperature and the pressure of a fixed mass of gas, with a fixed volume.
* Place the flask in a beaker of water.
* Heat the water.
* As the water heats up take a set of readings.
* The temperature of the water from the thermometer
* The pressure of the gas from the bourdon gauge
* Draw graph of pressure against temperature
110
State one source of gamma radiation
* Stars
* Some radioactive substances (e.g. Cobalt 60)
111
What does an electric field line show?
The direction a positive charge would move in that field.
112
What is the energy change in a photovoltaic cell?
Light to electrical
113
What is meant by refraction?
Refraction is the change of speed of light as it enters a different medium - often observed as a change in direction.
114
How is the period of a satellite effected by the orbiting altitude/height?
The bigger the orbiting altitude / height the longer the period orbit.
115
How can a space rocket be slowed down in space?
Reverse the thrusters to provide an unbalanced force backwards to slow you down.
116
State one source of gamma radiation
* Stars
* Some radioactive substances (e.g. Cobalt 60)
117
If you heat a conductor, what happens to it's resistance?
It increases
118
What temperature does absolute zero occur at?
0 K or -273 OC.
119
What type of spectrum is this?
Continuous spectrum
120
Which circuit component is represented by the following diagram?
Diode
121
State one use for radio waves.
* Radio/TV broadcasting
* Aircraft and shipping bands
* Radio waves detected from space are used by astronomers to find out what objects are made from
122
Explain the difference between average and instantaneous speed.
Average speed is over a long period of time, Instantaneous speed is the speed over a very short period of time.
123
How is a uniform electric field represented?
Evenly spaced field lines
124
What are the forces acting on a space rocket at launch?
* Weight - downwards
* Friction/air resistance - downwards
* Engine thrust upwards
125
What type of wave is a microwave?
Transverse.
126
Explain how snow shoes prevent you sinking into the snow.
Snow shoes have a large area. So the force of the person (weight) is spread over a larger area so the pressure exterted on the snow is less as P = F/A
127
What is electric charge?
An electric charge occurs when there are fewer or more electrons than protons.
128
What is the estimated age of the universe?
14 billion years
129
Explain how a radiation film badge is used to monitor the exposure to radiation.
* Badge has several windows in it made from different materials - when the film is developed the type of radiation can be identified by which windows have been penetrated by the radiation
* The darker the film behind the windows the more radiation the badge has been exposed to.
130
What is meant by the critical angle?
The angle of incidence that gives an angle of refraction of ninety degrees.
Red lines on diagram illustrate this.
131
Describe how to calculate acceleration from a veocity - time graph.
* Pick two pints on the slope.
* u = initial speed-read it off the graph,
* v = final speed-read it off the graph,
* t = time to go from the initial to the final speed.
* Then use a = (v-u)/t
132
What is the energy change in a motor?
Electrical to kinetic
133
What is meant by an acceleration of 15ms-2 ?
The velocity increases by 15ms-1 every second.
134
What is a fuse?
Safety device that protects the flex
135
What is the symbol for a voltmeter?
Circle with a V in it
136
What is the energy change in a loudspeaker?
Electrical to sound
137
Name 3 transverse waves.
* Radio
* Microwave
* Infrared
* Visible light
* Ultraviolet
* X-rays
* Gamma rays
* Water waves
138
What is the shape of a concave lens?
See image
139
State one detector of Ultraviolet light.
* Some chemicals glow or fluoresce under it
* photocells
140
What happens if two positive charges are brought together?
They repel each other
141
In the hills you can sometimes pick up a radio signal but not a television signal?
Radio waves are longer wavelengths than television waves.
Radio waves diffract more and can reach the receiver.
142
An object travels at a constant speed of 10ms-1. What can be said about the forces on it?
The forces are balanced
143
What is the difference in the diffraction pattern produced by waves passing through a wide and a narrow gap? (Wavelength is the same)
The narrower the gap, the more diffraction that occurs.
144
In an atom which particle orbits the nucleus?
Electron
145
State one use for gamma radiation.
* Used as a tracer in medicine
* Used to treat cancer
* Sterilisation of operating instruments
* In industry, radioactive "tracer" substances can be put into pipes and machinery, then we can detect where the substances go.
* Gamma rays kill microbes, and are used to so that it will keep fresh for longer. This is known as "irradiated" food.
* Checking for cracks in aeroplane wings and joints
146
What happens if you increase the resistance in a circuit?
The current will decrease
147
Name three scalar quantities
* Distance
* Time
* Speed
* Mass
* Energy
148
Suggest a way that we say 'energy is lost' (not converted to the type of energy we want)?
* Heat lost to the surroundings due to friction
* Sound energy lost to air because of vibrations
* Energy lost as heat to the surroundings
* Heat lost in heating up a container instead of the substance in it
149
What would happen to an electron being fired through the electric field below?
It would experience a force and be attracted to the positive plate.
150
What is meant by a light year?
The distance that light could travel in one year.
151
What does this velocity-time graph show?
Constant acceleration
152
Which circuit component is represented by the following diagram?
Light Emitting Diode
153
What type of current is represented by this oscilloscope image?
DC
154
What happens if two negative charges are brought together?
They repel each other
155
Which particles are in the nucleus of the atom?
Protons and Neutrons
156
State a source of natural background radiation.
1) **Rocks**: Some rocks such as granite or pitchblende are high in radioactivity
2) **Food**: Food can be slightly radioactive because of the soil it has been grown in.
3) **Body**: Contains Potassium 40 which is radioactive.
4) **Cosmic Rays**: Radiation from the Sun and outer space. The atmosphere will absorb most of this.
5) **Radioactive gases**: Radon and Thoron gases make up most of the dosage you will receive from background radiation. The gases come from rocks underground and the amount you are exposed to depends on the geology of where you live.
157
What is meant by the potential difference (voltage) of a supply?
It is the number of Joules of energy given to each coulomb of charge passing through the cell
158
Give an advantage of producing electricity using a nuclear fission reactor.
* Do not produce greenhouse gases – Carbon dioxide, methane, nitrous oxide
* Do not rely on fossil fuels which are in short supply
* Huge amount of energy from a small amount of fuel
* Small amount of waste produced
* Reliable source of energy (Unlike solar or wind)
159
These two block of wood have identical mass. Explain which exerts the greatest pressure.
* Both blocks have the same mass, so as W=mg will exert the same force down on the surface.
* Block B is sitting so that a small area sits on the surface, so as P = F/A it will exert a larger pressure.
160
What is the difference between a vector and a scalar quantity?
A scalar needs size/magnitude to be described correctly. A vector needs size/ magnitude and direction to be described correctly.
161
How does light travel through an optical fibre?
It travels by Total Internal Reflection
162
What is meant by the wavelength of a wave?
It is the distance from a point on one wave to the same point on the next.
163
An astronaut has a mass of 50kg. What will happen to the astronauts weight on the Moon?
The weight will decrease as there is a lower gravitaional field strength on the Moon.
164
State one detector of microwaves.
Aerial
165
An astronaut has a mass of 50kg. What will happen to the astronauts mass on the Moon?
It stays at 50kg. Mass does not change.
166
What would the field lines around a positive point charge look like?
Field lines show direction away from the positive point charge.
167
What will an unbalanced force cause?
Acceleration
168
What is the stated value of the mains?
230V, 50Hz
169
What are the issues of potential exposure to radiation?
Can cause
* cataracts
* increased risk of cancer
* damage to DNA and genetic material
170
What is the energy change in a loudspeaker?
Electrical to sound
171
What does the area under the velocity-time graph give?
The distance travelled
172
What is the energy change in a microphone?
Sound to electrical
173
What happens if you unscrew one of the lamps in the circuit below? Why?
The other lamps go out. There is a break in the circuit and the current does not have a complete route to the battery.
174
How can you identify a series circuit?
It is a circuit with only one path round it.
175
Describe an experiment to investigate the relationship between the the pressure and the volume of a fixed mass of gas, at a constant temperature.
Boyles Law:
* Pump is used to put pressure on oil which puts pressure on a fixed mass of trapped gas.
* Valve is closed.
* Volume of air column is read off the scale.
* Pressure is read off the bourdon gauge.
* Valve is opened and closed to change the pressure to get a set of readings.
* Draw graph of pressure against volume.
176
Which circuit component is represented by the following diagram?
Photovoltaic cell / solar cell
177
State one method of monitoring exposure to radiation.
Radiation film badge.
178
What is the rule for voltages in a parallel circuit?
The voltage across each branch is equal to the supply voltage.
179
What is an exoplanet?
A planet orbiting a sun outside our solar system.
180
Which circuit component is represented by the following diagram?
Light Dependent Resistor
181
What is the rule for voltages in a series circuit?
The voltage across each component added together is equal to the supply voltage.
182
Explain how a skydiver reaches terminal velocity.
* When the skydiver jumps out of a plane his initial vertical velocity is zero.
* His weight causes him to accelerate towards the ground. (Weight = Force = ma)
* As the skydivers velocity increases the air resistance upwards increases too.
* So the unbalanced force down becomes less, so there is less aceleration towards the ground. (Weight - air resistance = Unbalanced Force = ma)
* Eventually the weight downwards is equal and opposite to the air resistance upwards.
* This is a balanced force so the skydiver reaches terminal velocity.
183
What type of current is represented by this oscilloscope image?
DC
184
What is the energy change in an LED?
Electrical to light
185
Which circuit component is represented by the following diagram?
Lamp
186
What is a planet?
A ball of mass that
* orbits a sun
* has enough mass to be almost round
* is not a moon of another object
* has removed debris from the area round the orbit
187
State one use for visible light.
* We use light to see!
* Lasers are visible light and are used in Xbox, Playstation, Bluray player, DVD (where the light is reflected from the tiny pits in the disc, and the pattern is detected and translated into sound or data)
* Lasers also used in laser printers
* In aircraft weapon aiming systems.
188
What is the function of a MOSFET?
Electronic switch
189
State a device that can be used in a temperature sensor
Thermistor
190
What is acceleration?
Acceleration is the rate of change of velocity or the change in velocity per second.
191
Which circuit component is represented by the following diagram?
Microphone
192
What two factors effect the running cost of an appliance?
The time it is used for The power rating of the appliance
193
What does this velocity-time graph show?
Constant velocity
194
What is the energy change in a buzzer?
Electrical to sound
195
Explain how electrostatics can be used in paint spraying a car.
Car is connected to a negative terminal so that it is negatively charged.
Spray gun is made positively charged so the paint particles are positive.
The poistive paint is attracted to the negative car.
Areas of the car already covered in paint will repel any more charged paint.
196
Using Kinetic Theory explain what happens to the pressure if you increase the temperature of a fixed mass gas in a fixed volume container?
* Pressure is caused by the force of particles hitting the sides of the container.
* The temperature is increased. The particles gain kinetic energy.
* They will move faster and so hit the sides of the container more often and with a greater velocity so increasing the force.
* So the pressure increases.
197
What happens if two negative charges are brought together?
They repel each other
198
What is meant by fusion?
Fusion is when two nuclei of smaller mass number combine to form a nucleus of larger mass number.
199
When would you use a relay?
To switch on a high current ciruit using a low current circuit for safety.
200
What is meant by streamlining?
Streamlining is changing the shape of an object to reduce air/water resistance
201
How can the issue of manoeuvring in space be overcome?
Use of reverse thrusters.
202
Name one place that electrostatics can be used.
* Laser printers
* Paints spraying
* Cling film
* Forensic science
* Dust removal
* Electrostatic precipitators
* Electrostatic separators
203
Name the members of the electromagnetic spectrum, from lowest to highest frequency.
(Ronald Mcdonald Is Very Ugly eXclaimed George)
* Radio
* Microwave
* Infrared
* Visible Light
* Ultraviolet
* X-rays
* Gamma radiation
204
How can a parallel circuit be identified?
It is a circuit with more than one path round it.
205
Which circuit component is represented by the following diagram?
Variable Resistor
206
What is the symbol for an Ohmmeter?
Circle with an Omega in it
207
What happens if a positive and a negative charge are brought together?
They attract each other
208
What is the difference between real and apparent depth? Explain how this happens.
We think that the water is shallower than it actually is. (apparent depth)
This is because
* The light is refracted at the water/air boundary and changes direction away from the normal
* Our eyes/brain assume that light travels in straight lines.
209
What is a dwarf planet?
A dwarf planet
* Orbits a sun
* has enough mass to be almost round
* is not a moon of another object
* HAS NOT removed debris around area of the orbit
210
What is meant by a chain reaction?
A chain reaction is when a neutrons causes fission and releases more neutrons. The neutrons produced in the fission reaction, go on to cause their own fission reactions.
211
What is the difference in the two waves shown below?
The top wave has a bigger amplitude and so has more energy.
(Or the bottom wave has a smaller amplitude so has less energy)
212
What is the shape of a convex lens.
See image
213
What is meant by the 'normal'?
An imaginary line drawn at ninety degrees to the surface that all angles are measured from.
214
Which line on the graph represents the largest acceleration?
Blue Line - it has the steepest gradient
215
Which circuit component is represented by the following diagram?
Switch
216
Explain how a satellite stays in orbit.
Satellite has a constant horizontal velocity.
Satellite has a constant vertical acceleration due to the gravitational field strength of the planet.
This gives a curved trajectory.
The planet is curved so the satellite remains in orbit.
217
Which circuit component is represented by the following diagram?
Motor
218
Describe how to measure the speed of sound using the equipment below.
* Make a loud sound to the left of the first microphone.
* When the sound reaches microphone one it starts the fast timer, when the sound reaches the second microphone this stops the timer.
* Measure the distance between the microphones using a metre stick.
* The speed is calculated from distance between the microphones divided by the time on fast timer.
219
What will the amount of shielding required depend on?
The amount of shielding required to protect against different kinds of radiation depends on how much energy they have.
220
What is the radiation known as beta radiation?
It is a fast moving electron from the nucleus.
221
Describe how to measure average speed using the equipment below.
* Two light gates are connected to a timer.
* The car rolls down the slope.
* When the cardboard breaks the first lightgate beam it starts the timer. When the cardboard breaks the second lightgate beam it stops the timer.
* The timer records the time taken to go from the first to the second light gate.
* Measure the distance between the two light gates using a metre stick.
* Calculate the speed = distance between light gates / time on timer
222
For a projectile fired horizontally, what would the vertical velocity time graph look like?
It would show a constant acceleration, a line of gradient = 9.8ms-2
223
Where does the energy come from in a fission and a fusion reaction?
Some of the mass is converted into energy.
224
How can power losses be reduced in transmission lines?
By increasing the transmission voltage and so decreasing teh transmission current. Power loss P = I2R, so if the current is reduced the power lost is reduced.
225
What causes friction?
Two surfaces rubbing together
226
Which circuit component is represented by the following diagram?
Capacitor
227
What is meant by temperature?
It is a measure of the mean kinetic energy of the particles.
228
What is the difference in the two waves shown below?
The bottom wave has a higher frequency. (Or the top wave has a lower frequency)
229
What is meant by ionisation?
It is when an atom gains or loses an electron to become charged.
230
Which circuit component is represented by the following diagram?
Variable Resistor
231
Describe how to measure average speed.
* Mark a start line and a finish line.
* Measure the distance between the start and finish line with a ruler/metre stick.
* Start a stopwatch when the object crosses the start line and stop it when the object crosses the finish line.
* Calculate the average speed = distance between start and finish / time on stopwatch
232
Which circuit component is represented by the following diagram?
Motor
233
What is the symbol for an ammeter?
Circle with an A in it.
234
What is meant by absorbed dose?
The energy absorbed per unit mass
235
What is meant by the frequency of a wave?
The number of waves per second.
236
State an advantage of a fusion reactor.
* Releases massive amounts of energy
* It is sustainable (unlikely to run out)
* No greenhouse gases
* No risk of meltdown
237
What type of spectrum is this?
Line Spectrum
238
State one source of radio waves.
* Transmitter
* Stars
239
State one way that travelling the large distance in space could be overcome.
* Use an ion drive
* Gravity assist (catapult) from a planet, moon or fast moving asteroid
240
How does is the frequency of a wave related to it's energy?
The higher the frequency the more energy the wave has.
241
What is meant by the amplitude of a wave?
It is the distance from the centre of the wave to the crest or trough.
242
What is meant by diffraction?
It is the bending of waves round an object.
243
How does the observable universe let us estimate the age of the universe?
The furthest point that we can detect is the distance which light must have travelled for the whole age of the universe.
This allows us to work out the approximate time of travel and so teh age of the universe.
244
What precautions should be taken when storing a radioactive source?
* Source should be clearly labelled as to type
* Stored in lead lined boxes
245
What is the rule for current in a parallel circuit?
The supply current is equal to the current in each branch added together.
246
State one source of X-rays.
* Stars
* Nebula
247
What are the particles in the nucleus called?
Protons and neutrons
248
Which circuit component is represented by the following diagram?
Cell
249
Which circuit component is represented by the following diagram?
Lamp
250
State one detector of radio waves.
Aerial
251
If you heat a conductor, what happens to it's resistance?
It increases
252
State one source of microwaves.
* Transmitter
* Magnetron
253
What path will the ray of light take as it passes through the glass prism?
Light ray is refracted at air/glass boundary and glass/ air boundary. Both result in a change of direction.
As it enters the block the speed of the light decreases and it changes direction towards the normal.
As it leaves the block the speed of the light increases and it changes direction away from the normal.
254
State one use for infrared radiation.
* Skin emits infrared light we can be seen in the dark by someone using night vision goggles.
* Astronomers use infrared to give extra information about space. Infrared light maps the dust between stars.
* Can be used to create thermograms which are used in medicine as a diagnostic tool for cancer, deep vein thrombosis(DVT), circulation problems (Reynaulds syndrome)
* Remote controls for TVs, DVD, Bluray players etc
* Physiotherapists use heat lamps to help heal sports injuries
255
What do waves transfer?
Energy
256
How can you indicate a weaker electric field?
Less field lines
257
What is a geostationary satellite?
Satellites with a period of 24 hours and orbit at a height of 36000km.
258
Give a disadvantage of producing electricity using a nuclear fission reactor.
* The waste produced is radioactive. It has to be stored safely for a long time.
* Uranium is a non-renewable fuel.
* Risk of radioactive materials being released into the environment if there is an accident.
* Expensive to decommission nuclear power stations at the end of their useful life.
259
You are 10km from a thunder storm. You count 15 seconds between seeing the lightning and hearing the thunder. How do you calculate how far away the storm is?
Use d = vt
Where v is the speed of sound.
t is 15 seconds.
260
State one use for microwave radiation.
* Mobile phone communications
* Used to heat/cook food
* Microwaves in space are used by astronomers to learn about the structure of nearby galaxies, and our own Milky Way
* Microwaves are also used by fixed traffic
* Radar
261
How should a diode or LED be connected with a battery to light correctly?
Small line on battery points to small line on LED or diode.
262
What is the rule for selecting a fuse from a power rating?
Appliances less than 720W use a 3A fuse Appliances more than 720W use a 13A fuse
263
What is the energy change in a buzzer?
Electrical to sound
264
What is the rule for current in a parallel circuit?
The supply current is equal to the current in each branch added together.
265
What is a Light Dependent Resistor?
A resistor whose resistance changes with changes in light level
266
List some benefits of space exploration.
* Satellite communications
* GPS and SatNav technologies
* Weather forecasting / storm tracking
* Improved mapping
* Spin off technologies - hand held drills, portable DVD players, memory foam
* Space exploration e.g Hubble telescope, International space station
267
Two 1kg blocks of metal are heated up. Block A and Block B. Each block is made from a different material. They are both supplied with 10000J on energy. Block B has the biggest temperature change.
What can you say about Block B compared to Block A?
Block B has a lower specific heat capacity.
268
What is specific heat capacity?
The number of Joules of energy needed to raise 1kg of a substance by 1OC.
269
What is the difference between speed and velocity?
Speed is a scalar and is equal to distance divided by time. Velocity is a vector and is displacement divided by time, with a direction.
270
Explain how a fuse works.
A fuse is a thin wire. If too much current passes through it, it will get hot and melt. This breaks the circuit.
271
Which circuit component is represented by the following diagram?
Transistor
272
Explain why re-entering the atmosphere poses a challenge.
* When a space craft is in space there is no friction as space is a vacuum.
* When you re-enter the Earth’s atmosphere you go from no friction to lots of friction (caused by the atmosphere).
* The result is that the space craft loses kinetic energy and slows down.
* However due to conservation of energy, the energy is not lost but is converted to heat.
* The outside of the space craft becomes incredibly hot.
* This means that the space vehicle requires thermal shielding.
273
What is meant by background radiation?
It is the radiation that is all around us.
274
What is the energy change in an LED?
Electrical to light
275
Explain how to measure acceleration using the equipment shown below and a stop watch.
* When the cardboard passes through the first light gate the timer attached to it records this time.
* Measure the length of the card with a ruler.
* The initial velocity, u = length of card / time on timer
* As the car rolls down the ramp, start the stop watch when it reaches the first light gate and when it reaches the second light gate stop the stop watch.
* This is t, the time for the change in velocity.
* When the cardboard passes through the second light gate the timer attached to it records this time.
* The final velocity, v = length of card / time on timer
* Then calculate acceleration, a = (v-u)/t
276
How can the electromagnetic spectrum be used to obtain information about objects in space?
Different objects in space emit different signals that we can detect to get information about the object.
Different frequencies require different detectors.
277
What is a thermistor?
A resistor whose resistance changes with changes in temperature
278
Which colour of light is refracted least in a triangular prism when white light is shone through it?
Red light
279
When would you use a relay?
To switch on a high current ciruit using a low current circuit for safety.
280
State one source of ultraviolet light.
* Sun
* Special Lamps
281
What is meant by heat?
It is the energy of the substance.
282
What is meant by absolute zero?
* When gas particles have no energy and cannot move or collide with the sides of the container.
* They have no more kinetic energy to remove.
* Temperature cannot go below this.
283
What is the function of a MOSFET?
Electronic switch
284
Describe a streamlined shape
* Low to the ground
* Smooth
* Have curves
285
How should an ammeter be connected to measure the current in a component?
It should be connected in series with the component
286
What does the area under this velocity time graph give?
If positive area and negative area are subtracted it gives the displacement. If the total area is calculated it gives the distance travelled.
287
Which circuit component is represented by the following diagram?
Switch
288
What is a sun?
A star is called a sun if it is the centre of a planetary system.
289
What is the charge on an electron?
Negative
290
What would happen to an electron being fired through the electric field below?
It would experience a force and be attracted to the positive plate.
291
What is the effect of an electric field on a charge?
The charge will experience a force.
292
Which circuit component is represented by the following diagram?
Photovoltaic cell / solar cell
293
What would the field lines around a negative point charge look like?
Field lines show direction towards the negative point charge
294
How should an ammeter be connected to measure the current in a component?
It should be connected in series with the component
295
Which device measures voltage?
Voltmeter
296
How can you indicate a weaker electric field?
Less field lines
297
Which circuit component is represented by the following diagram?
Fuse
298
When is work done?
When a force is exterted over a certain distance.
299
Using Kinetic Theory explain what happens to the volume if you increase the temperature of a fixed mass gas at a fixed pressure?
* Pressure is caused by the force of particles hitting the sides of the container.
* The temperature is increased. The particles gain kinetic energy.
* They will move faster and so hit the sides of the container more often and with a greater velocity and so greater force.
* So the pressure increases.
* This puts pressure on a rubber bung/bead of mercury etc. and it moves. It will move until the pressure inside the container = pressure outside the container.
* So the volume will increase.
300
Which device measures resistance?
Ohmmeter
301
What is the rule for voltages in a series circuit?
The voltage across each component added together is equal to the supply voltage.
302
What type of wave is a water wave?
Transverse.
303
What is electric charge?
An electric charge occurs when there are fewer or more electrons than protons.
304
For the diagram of the atom name the parts.
305
How can you calculate the distance that is one light year?
* d=vt
* d = 3 x 108 x (365.25 x 24 x 60 x 60)
306
What is the annual effective dose limit for a radiation worker?
20mSv
307
What does the gradient of the line on velocity - time graph represent?
The acceleration
308
Which circuit component is represented by the following diagram?
Thermistor
309
When does an object have kinetic energy?
When it is moving.
310
What are the possible dangers of space exploration?
* pressure differential
* exposure to radiation
* fuel load on take-off
* re-entry through atmosphere
311
In the diagram below, where is;
* the normal ?
* the angle of incidence?
* the angle or refraction?
See diagram
312
What is current?
The charge transferred per second
313
What causes pressure of a gas in a container?
Gas particles hitting the sides of a container
314
Explain an experiment to measure the half life of a source.
* With **no** source present record the number of counts in one minute using the G-M tube and counter. This is the ‘background radiation’.
* Put source in position. The stop clock and the counter are started at the same time.
* Take a reading of the counts per minute every minute. Do this for 10 minutes.
* The background radiation is subtracted from each of the readings so that the counts / minute for the source are recorded.
* A graph is plotted of counts / minute against time. The half-life is calculated from the graph.
315
State one use for ultraviolet radiation.
* UV lamp in a chip shops. (The UV attracts insects, which are electrocuted by high-voltage wires near the lamp - so they won't land on the food and contaminate it.)
* Detecting forged bank notes in shops (security markings fluoresce under UV light)
* Hardening some dental fillings
* Night club lighting
* UV security pens to mark property
* Killing microbes – Sterilising surgical equipment, air in operating theatres
* Food and drug companies use UV lamps to sterilise products
* Used by the body to produce vitamin D
* Doctors can use it to treat Vitamin D deficiency, acne etc.
316
Which member of the electromagnetic spectrum has the most energy?
Gamma radiation as it has the highest frequency
317
What is the rule for selecting a fuse from a power rating?
Appliances less than 720W use a 3A fuse Appliances more than 720W use a 13A fuse
318
What is meant by a longitudinal wave?
A wave that vibrates along the direction of travel.In a longitudinal wave, the motion of the medium is parallel to the direction of the wave.
319
What is the impact of ionisation on living cells?
It can kill them.
320
What is the effect of an electric field on a charge?
The charge will experience a force.
321
Using Newton's 3rd Law explain how a space rocket takes off.
Engines push exhaust gases downwards. Exhaust gases push engines upwards.
322
What is meant by the universe?
The universe is all of time and space and its contents.
323
Newtons 1st Law is about balanced forces, what two things can happen if a balanced force acts on an object?
* Remains stationary
* Travels at a constant speed in a straight line
324
Why is containment an issue for fusion reactors?
The high temperatures of the plasma would vapourise any materials that we currently know.
325
What is meant by pressure?
The force per unit area
326
State two place a variable resistor can be used.
Light dimmer switch sped control on Scalextric cars volume control on a radio
327
What does a capacitor do?
Stores charge or energy
328
What is the energy change in a microphone?
Sound to electrical
329
What is the stated value of the mains?
230V, 50Hz
330
What happens if a positive and a negative charge are brought together?
They attract each other
331
What is meant by a transverse wave?
A wave that vibrates at ninety degrees to the direction of travel. A transverse wave is a wave in which the motion of the medium is at right angles to the direction of the wave.
332
What type of current is represented by this oscilloscope image?
AC
333
Which wave property is illustrated in the diagram below?
The amplitude of a wave.
334
What happens if you unscrew one of the lamps in the circuit below? Why?
The other lamps go out. There is a break in the circuit and the current does not have a complete route to the battery.
335
Which circuit component is represented by the following diagram?
Battery
336
Which is the least ionising radiation?
Gamma
337
What is meant by shielding?
Shielding means having something that will absorb radiation between you and the source of the radiation.
338
A temperature - time graph is shown below. What is happening at point B on the graph?
* The material is changing state.
* From solid to liquid
339
What happens to the speed of light as it travels from air into glass?
The speed of light in glass is slower than the speed of light in air.
340
State one source of infrared.
* Stars
* Lamps
* Flames
341
What is the energy change in a motor?
Electrical to kinetic
342
Give at least 2 uses for radiation.
* Gamma rays are used for radiotherapy which is a cancer treatment
* Thickness control of paper or metal sheet for example.
* Gamma radiation can be used to sterilise medical instruments
* Radio-carbon dating
* Tracers - can be used in industry in pipes to look for cracks or in the human body to check for blockages
343
What is the charge on a neutron?
No charge
344
What is the function of a transistor?
Electronic switch
345
State one detector of infrared
* photodiode
* phototransistor
346
If an object is projected horizontally from a cliff, how can the height of the cliff be calculated?
* Sketch a vertical velocity-time graph
* Due to gravitational field strength the velocity will increase vertically by 9.8ms-1.
* Calculate the area under the velocity-time this is equal to the verical height of the cliff.
347
You are 10km from a thunder storm. You count 15 seconds between seeing the lightning and hearing the thunder. You repeat this after the next lightning strike, the time between the lightning and the thunder is now 10 seconds. What does this tell you?
The storm has moved closer to you.
348
State a device that can be used in a light sensor
LDR
349
How can a parallel circuit be identified?
It is a circuit with more than one path round it.
350
Which device measures resistance?
Ohmmeter
351
Does a light ray always change direction when it undergoes refraction?
No.
352
What is the annual effective dose limit for a member of the public?
1mSv
353
Which circuit component is represented by the following diagram?
Fuse
354
Explain how a satellite stays in orbit.
Satellite has a constant horizontal velocity.
Satellite has a constant vertical acceleration due to the gravitational field strength of the planet.
This gives a curved trajectory.
The planet is curved so the satellite remains in orbit.
355
What effect does a concave lens have on light rays?
It causes them to diverge - by refraction of the light
356
What is the energy change in a buzzer?
Electrical to sound
357
What happens if two positive charges are brought together?
They repel each other
358
What is power?
The energy used per second
359
What is the rule for current in a series circuit?
The current is the same everywhere
360
You are 5km away from a thunder storm. What reaches you first - the thunder or the lighning? Explain your answer.
The lightning. The speed of light is faster than the speed of sound.
361
What is meant by a corrected count rate?
It is when the background radiation is subtracted from the radiation measured so that the reading is caused by the source not background radiation.
362
Explain how a fuse works.
A fuse is a thin wire. If too much current passes through it, it will get hot and melt. This breaks the circuit.
363
Which circuit component is represented by the following diagram?
Microphone
364
What is the charge on a neutron?
No charge
365
Which circuit component is represented by the following diagram?
Cell
366
How can you reduce your exposure to radiation when you are working with it?
* Limit the time you have the source out (only get it when you need it)
* Handle only using tongs
* Keep the source at arm's length
* Wash hands before and after use
* Do not eat while handling it
* Wear lead lined gloves/apron and safety goggles
367
What is DC?
Direct current. Electrons move in one direction only.
368
What is Newton's 3rd Law?
For every action force there is an equal but opposite reaction force
369
Name one place that electrostatics can be used.
* Laser printers
* Paints spraying
* Cling film
* Forensic science
* Dust removal
* Electrostatic precipitators
* Electrostatic separators
370
What is a solar system?
It is a system bound by gravity, made up of a sun and the objects that orbit it.
371
What would the field lines look between parallel plates?
Field lines run from positive to negative plate, with a bulge at the ends of the parallel plate.
372
Which circuit component is represented by the following diagram?
Resistor
373
The graph below shows a temperature - time graph. Points B and D show changes in state. Explain why this can be identified from the graph.
When a substance changes state the temperature remains constant. (Shown by horizontal line on graph)
374
Which device measures voltage?
Voltmeter
375
How can you increases friction?
* Increase the area of the rubbing surfaces
* Make the rubbing surfaces rougher
* Push the rubbing surfaces togerther more
* Increase the speed that the surafces are rubbed together
376
How should a voltmeter be connected to measure the voltage across a component?
It should be connected across the component
377
What is the charge on a beta particle?
Negative
378
What is the difference between distance and displacement?
Distance is the length of the path you actually take and it is a scalar, displacement is the straight line distance between where you started and finished including a direction as it is a vector.
379
What is the charge on an electron?
Negative
380
What are the products in a fission reaction in a nuclear reactor.
* fission fragments (smaller mass nucleii)
* Heat energy
* More neutrons
381
Name one source of DC
Battery
382
What are the three types of radiation?
* alpha
* beta
* gamma
383
Which circuit component is represented by the following diagram?
Battery
384
Which component does the symbol represent?
Buzzer
385
How can you convert between OC (degrees Celsius) and K (Kelvin)?
Temperature in degrees Celsius + 273
386
Which is the most ionising radiation?
alpha
387
Which circuit component is represented by the following diagram?
Light Emitting Diode
388
How can you indicate a stronger electric field?
More field lines
389
What is the energy change in a buzzer?
Electrical to sound
390
What would the field lines around a negative point charge look like?
Field lines show direction towards the negative point charge
391
State one detector of gamma radiation
* Photographic film
* GM Tube
* Bubble chamber
392
How can you decrease friction?
* Decrease the area of the rubbing surfaces
* Make the rubbing surfaces smoother
* Push the rubbing surfaces together less
* Decrease the speed that the surfaces are rubbed together
* Lubricate/oil/ wax the surfaces
* Streamline the object
393
What is AC?
Alternating current. The electrons change direction, moving backwards and forwards, many times in a second.
394
What is equivalent dose?
It is a way of taking into account the absorbed dose and the type of radiation you are exposed to.
395
What are the two main challenges of re-entry?
* Angle of re-entry
* High temperatures / heating effect
396
Explain why a projectile follows a curved trajectory.
* It has a constant horizontal velocity
* It has a constant vertical acceleration downwards due to gravity
397
State one detector of X-rays
Photographic film
398
Describe how to measure the speed of sound with two students using a clapper board, stop watch and trundle wheel.
* One student takes the clapperboard and stands still.
* The other students takes the stop watch and uses the trundle wheel to measure a set distance away.
* The first student shuts the clapper board.
* The other student starts the stop watch when they see the clapper shut and stops it when they hear the sound.
* Speed of sound is calculated by distance between the students divided by the time on stop watch.
399
What are the main parts of an atom?
See diagram
400
What is the energy change in a photovoltaic cell?
Light to electrical
401
State the equipment you would need to measure the half life of a source.
* Timer
* G-M Tube and counter
* Source of radiation
402
What is the charge on an alpha particle?
Positive
403
What two factors effect the running cost of an appliance?
The time it is used for The power rating of the appliance
404
Which colour of light is refracted most in a triangular prism when white light is shone through it?
Blue light
405
What will absorb gamma radiation?
Several centimetres of lead
406
When does an object have potential energy?
When it is lifted through a height.
407
What does an electric field line show?
The direction a positive charge would move in that field.
408
Name one source of DC
Battery
409
State a device that can be used in a temperature sensor
Thermistor
410
What is the charge on a proton?
Positive
411
What happens when white light is shone through a triangular prism as shown?
The light is refracted and produces a spectrum.
412
What does a capacitor do?
Stores charge or energy
413
How can a space rocket be slowed down in space?
Reverse the thrusters to provide an unbalanced force backwards to slow you down.
414
What is a Light Dependent Resistor?
A resistor whose resistance changes with changes in light level
415
State a source of man-made background radiation.
1) Weapons testing
2) Waste from the Nuclear industry
3) Medical uses: Having an X-ray, CT scan, barium meal etc.
416
What is velocity?
Displacement travelled per second.
417
What is current?
The charge transferred per second
418
What is the charge on a neutron?
No charge
419
Explain why being stood on by a stilletto heel is painful.
Stileto heels have very small areas. So the force of the person (weight) is spread over a very small area so the pressure exterted is high as P = F/A
420
What is conservation of energy?
Energy cannot be created or destroyed it can only be transferred from one type to another.
421
What will be the voltage across a capacitor when it is fully charged?
The supply voltage.
422
A temperature - time graph is shown below. What is happening at point C on the graph?
The temperature of the liquid is increasing.
423
Which device measures current?
Ammeter
424
Using Kinetic Theory explain what happens to the pressure if you decrease the volume of a fixed mass gas at a constant temperature?
* Pressure is caused by the force of particles hitting the sides of the container.
* The volume is decreased. The particles have less room to move about and so hit the sides of the container more often increasing the force on the container.
* So the pressure increases.
425
How can power losses be reduced in transmission lines?
By increasing the transmission voltage and so decreasing teh transmission current. Power loss P = I2R, so if the current is reduced the power lost is reduced.
426
For the diagram of the atom name the parts.
427
What is the energy change in a buzzer?
Electrical to sound
428
Explain how electrostatics can be used in paint spraying a car.
Car is connected to a negative terminal so that it is negatively charged.
Spray gun is made positively charged so the paint particles are positive.
The poistive paint is attracted to the negative car.
Areas of the car already covered in paint will repel any more charged paint.
429
What does this velocity - time graph show?
Constant de-acceleration
430
What is meant by the period of a wave?
The time it takes one wave to pass a point.
431
A temperature - time graph is shown below. What is happening at point A on the graph?
The temperature of the solid material is rising.
432
State two challenges of space exploration.
* Travelling the large distances
* Manoeuvring
* Maintaining energy
433
State three detectors of radiation.
1. Photographic film
2. GM Tube
3. Scintillation counter
434
What path will the ray of light take as it passes through the glass prism?
Light ray still experiences a change of speed - it is still refracted but no directional change.
435
What are the issues with fuel load on take-off?
There is a massive amount of fuel being carried and a huge amount of heat is produced. This could lead to an explosion.
436
How can you tell from this oscilloscope image that this is AC?
The trace shows a change in direction
437
What is the difference between mass and weight?
Mass is a measure of the partcles that make an object up. Weight is a force caused by the gravitational field strength of a planet.
438
Describe how to calculate the half-life of a source from a graph.
# * Choose a ‘nice’ starting value e.g. 20,000Bq.
* Find the ‘time’ that this happens at e.g. 0 Hours.
* Once a half life has passed the activity will be 20,000÷2 = 10,000Bq.
* Find the time that this happens at from the graph – 12 Hours.
* Calculate the time for the change is 12 – 0 = 12 hours
439
Why is manoeuvring in space such an issue?
There is no friction to slow down.
440
How can the issue in maintaining energy in space be overcome?
Use solar cells angled towards the Sun.
441
Which circuit component is represented by the following diagram?
Light Dependent Resistor
442
Why is an LED normally connected in series with a resistor?
Resistor is to protect the LED by limiting the current in the LED.
443
What is meant by capacitance?
Charge stored per unit volt
444
Describe an experiment to investigate the relationship bewteen the volume and the temperature of a fixed mass of gas at a fixed pressure.
* A fixed mass of gas is trapped by a bead of mercury
* Place the capilary tube, thermometer and ruler/scale into the beaker of water.
* Heat the water.
* At different temperatures - measure the temperature of the gas from the thermometer and the volume from the ruler/scale.
* The pressure is kept constant as the bead of mercury is free to move so that the pressure reamins constant.
* Plot a graph of volume against temperature.
445
What will be the voltage across a capacitor when it is fully charged?
The supply voltage.
446
Which particles are in the nucleus of the atom?
Protons and Neutrons
447
What is the energy change in a lamp?
Electrical to light (+ heat)
448
What is latent heat of fusion?
The number of Joules of energy required to change 1kg of a solid to 1kg of a liquid with no temperature change.
449
Explain the energy change as the sledge slides down the hill.
* At the start the sledge has potential energy.
* As it starts to slide down the hill it loses potential energy and gains kinetic energy
* At the bottom of the hill the sldge has no potential energy it has all been transferred to kinetic energy.
* At any point on the slope the potential energy + the kinetic energy = potential energy at the top of the slope.
450
What is AC?
Alternating current. The electrons change direction, moving backwards and forwards, many times in a second.
451
What happens to a light ray as it travels from air into glass?
It will slow down and change direction towards the normal.
452
What is a star?
A ball of gas undergoing fusion that gives off heat and light.
453
What is the function of a transistor?
Electronic switch
454
How does a nuclear fission power station produce electrical energy?
* The nuclear reactor uses fission of Uranium to produce large amounts of heat energy.
* The heat energy is used to heat water.
* The water which is heated, turns into steam, is piped to turn a turbine.
* The steam makes the turbine turn. (Heat energy to Kinetic Energy)
* The turbine turns the generator to create electrical energy. (Kinetic to Electrical energy)
455
What is meant by fission?
Fission is when a nucleus of a large mass number splits into two nuclei of smaller mass numbers, with the release of energy and neutrons.
456
Why does a triangular prism produce a spectrum from white light?
Different frequencies/colours of light refract by different amounts.
457
Which wave property is illustrated below?
Wavelength
458
What is a balanced force?
Equal forces acting in opposite directions
459
A temperature - time graph is shown below. What is happening at point D on the graph?
* The material is changing state
* From a liquid to a gas.
460
What information can be extracted from the spectral lines from a star?
The elements present in the star.
461
Describe what is meant by an AC current
A current whose instantaneous value and direction changes with time.
