Whole Course Flashcards
Describe how a cyclist can streamline themself
- Crouch over the handlebars
- Wear tight lycra clothing
- Specially shaped helmet
What is meant by capacitance?
Charge stored per unit volt
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.
Explain how a fusion reactor could generate electrical energy.
- 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)
What is the energy chage in a battery?
Chemical to electrical
Which circuit component is represented by the following diagram?
MOSFET
What is an asteroid?
An asteroid is a small rocky and airless object that orbit the sun. They are too small to be planets.
What will absorb beta radiation?
A few millimetres of aluminium
How can you tell from this oscilloscope image that this is AC?
The trace shows a change in direction
What are the issues of pressure differential?
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.
What happens if light is shone onto a surface at an angle greater than the critical angle?
It is no longer refracted it is totally internally reflected.
What happens to a light ray as it travels from water into air?
It speeds up and changes direction away from the normal.
What does the path a projectile takes look like?
Curve
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.
What is the rule for voltages in a parallel circuit?
The voltage across each branch is equal to the supply voltage.
Why is maintaining energy such a big issue in space exploration?
Energy is required to maintain life support systems. It would be difficult to carry enough fuel so energy must be generated in space.
Name one source of AC
Mains supply
What is speed?
Distance travelled per second.
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.
What is conservation of energy?
Energy cannot be created or destroyed it can only be transferred from one type to another.
What is the charge on an electron?
Negative
State one source of visible light.
- The Sun
- Light bulbs
- Anything hot enough to glow
What would the field lines around a positive point charge look like?
Field lines show direction away from the positive point charge.
Which component does the symbol represent?
Buzzer
What will be the voltage across a capacitor when it is fully discharged?
Zero volts.
What is a fuse?
Safety device that protects the flex
What is the difference in the diffraction pattern in a long wavelength and a short wavelength passing an object?
The longer wavelength diffracts more.
What is the symbol for an ammeter?
Circle with an A in it.
State one detector of gamma radiation
- Photographic film
- GM Tube
- Bubble chamber
Which circuit component is represented by the following diagram?
Transistor
What is the ‘observable universe’?
The observable universe is the furthest point that we can ‘see’ or detect.
What is a galaxy?
A galaxy is a gravitationally bound system of stars, stellar remnants, gas, dust and dark matter.
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.
What is the radiation known as alpha particles?
It is a helium nucleus.
(It has 2 protons and 2 neutrons.)
How can you identify a series circuit?
It is a circuit with only one path round it.
What is the energy chage in a battery?
Chemical to electrical
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
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
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
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.
What is meant by equivalent dose rate?
Equivalent dose absorbed per unit time.
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.
Will long or short wavelengths diffract more?
Lomg wavelengths diffract more.
How is a uniform electric field represented?
Evenly spaced field lines
What is a moon?
A natural satellite
Why is an LED normally connected in series with a resistor?
Resistor is to protect the LED by limiting the current in the LED.
What is a thermistor?
A resistor whose resistance changes with changes in temperature
Which circuit component is represented by the following diagram?
Loudspeaker
What is work?
It is the measure of the energy used to move an object over a distance using a force.
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.
State two place a variable resistor can be used.
Light dimmer switch sped control on Scalextric cars volume control on a radio
Which circuit component is represented by the following diagram?
Resistor
What happens if you increase the resistance in a circuit?
The current will decrease
What type of wave is a sound wave?
Longitudinal.
What is the symbol for an Ohmmeter?
Circle with an Omega in it
Name one source of AC
Mains supply
What is the charge on a gamma ray?
No charge
Why is travelling large distance in space such an issue?
Carrying the fuel required would be impossible.
What is the radiation known as gamma radiation?
It is a wave and part of the electromagnetic spectrum.
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
What is the charge on a proton?
Positive
Should the engine force or the resultant force be used when calculating the acceleration of a space rocket on take off?
Resultant force
Name three vector quantities
- Displacement
- Velocity
- Acceleration
- Force
- Momentum
- Weight
What is meant by gravitational field strength?
Force per unit mass
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.
Which circuit component is represented by the following diagram?
Thermistor
What is the radiation weighting factor?
A number that takes into account the type of radiation you are exposed to.
How should a voltmeter be connected to measure the voltage across a component?
It should be connected across the component
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
What is the energy change in a lamp?
Electrical to light (+ heat)
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.
What happens to the object at point X?
It changes direction
What is the weight of an object in freefall?
0 Newtons
What effect is shown here?
Diffraction
Which circuit component is represented by the following diagram?
Diode
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.
Name a longitudinal wave.
Sound.
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.
What type of current is represented by this oscilloscope image?
AC
A temperature - time graph is shown below. What is happening at point E on the graph?
The temperature of the gas is increasing.
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
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.
How can you indicate a stronger electric field?
More field lines
What will absorb alpha radiation?
A few centimetres of air or a sheet of paper.
Which circuit component is represented by the following diagram?
Loudspeaker
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.
What is power?
The energy used per second
Which circuit component is represented by the following diagram?
MOSFET
Which circuit component is represented by the following diagram?
Capacitor
What will be the voltage across a capacitor when it is fully discharged?
Zero volts.
What is the annual effective dose of the average annual background radiation in the UK?
2.2mSv
What is meant by the activity of a source?
It is the number of decays/disintegrations per second
What is meant by gravitational field strength?
Force per unit mass
What is the charge on a proton?
Positive
Which device measures current?
Ammeter
State a device that can be used in a light sensor
LDR
State 2 issues that must be overcome in fusion reactors.
- The high temperatures required
- The high pressures required
How can you work out the resultant force acting on a space rocket at launch?
Resultant force = Engine thrust - (Weight + frictional forces)
What is DC?
Direct current. Electrons move in one direction only.
What is the symbol for a voltmeter?
Circle with a V in it
For a projectile fired horizontally, what would the horizontal velocity time graph look like?
Constant horizontal velocity - therefore a straight horizontal line.
What effect does a convex lens have on light rays?
The light rays converge to a focal point, by refraction of the light.
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)
What is the fuel in a nuclear fission reactor?
Uranium
State one detector of visible light.
- Retina in the eye,
- photographic film
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
What is the rule for current in a series circuit?
The current is the same everywhere
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.
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
State one source of gamma radiation
- Stars
- Some radioactive substances (e.g. Cobalt 60)
What does an electric field line show?
The direction a positive charge would move in that field.
What is the energy change in a photovoltaic cell?
Light to electrical
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.
How is the period of a satellite effected by the orbiting altitude/height?
The bigger the orbiting altitude / height the longer the period orbit.
How can a space rocket be slowed down in space?
Reverse the thrusters to provide an unbalanced force backwards to slow you down.
State one source of gamma radiation
- Stars
- Some radioactive substances (e.g. Cobalt 60)
If you heat a conductor, what happens to it’s resistance?
It increases
What temperature does absolute zero occur at?
0 K or -273 OC.
What type of spectrum is this?
Continuous spectrum
Which circuit component is represented by the following diagram?
Diode
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
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.
How is a uniform electric field represented?
Evenly spaced field lines
What are the forces acting on a space rocket at launch?
- Weight - downwards
- Friction/air resistance - downwards
- Engine thrust upwards
What type of wave is a microwave?
Transverse.
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
What is electric charge?
An electric charge occurs when there are fewer or more electrons than protons.
What is the estimated age of the universe?
14 billion years
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.
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.
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
What is the energy change in a motor?
Electrical to kinetic
What is meant by an acceleration of 15ms-2 ?
The velocity increases by 15ms-1 every second.
What is a fuse?
Safety device that protects the flex
What is the symbol for a voltmeter?
Circle with a V in it
What is the energy change in a loudspeaker?
Electrical to sound
Name 3 transverse waves.
- Radio
- Microwave
- Infrared
- Visible light
- Ultraviolet
- X-rays
- Gamma rays
- Water waves
What is the shape of a concave lens?
See image
State one detector of Ultraviolet light.
- Some chemicals glow or fluoresce under it
- photocells
What happens if two positive charges are brought together?
They repel each other
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.
An object travels at a constant speed of 10ms-1. What can be said about the forces on it?
The forces are balanced
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.
In an atom which particle orbits the nucleus?
Electron
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
What happens if you increase the resistance in a circuit?
The current will decrease
Name three scalar quantities
- Distance
- Time
- Speed
- Mass
- Energy
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
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.
What is meant by a light year?
The distance that light could travel in one year.
What does this velocity-time graph show?
Constant acceleration
Which circuit component is represented by the following diagram?
Light Emitting Diode
What type of current is represented by this oscilloscope image?
DC
What happens if two negative charges are brought together?
They repel each other
Which particles are in the nucleus of the atom?
Protons and Neutrons
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.
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
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)
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.
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.
How does light travel through an optical fibre?
It travels by Total Internal Reflection
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.
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.
State one detector of microwaves.
Aerial
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.
What would the field lines around a positive point charge look like?
Field lines show direction away from the positive point charge.
What will an unbalanced force cause?
Acceleration
What is the stated value of the mains?
230V, 50Hz
What are the issues of potential exposure to radiation?
Can cause
- cataracts
- increased risk of cancer
- damage to DNA and genetic material
What is the energy change in a loudspeaker?
Electrical to sound
What does the area under the velocity-time graph give?
The distance travelled
What is the energy change in a microphone?
Sound to electrical
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.
How can you identify a series circuit?
It is a circuit with only one path round it.
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.
Which circuit component is represented by the following diagram?
Photovoltaic cell / solar cell
State one method of monitoring exposure to radiation.
Radiation film badge.
What is the rule for voltages in a parallel circuit?
The voltage across each branch is equal to the supply voltage.
What is an exoplanet?
A planet orbiting a sun outside our solar system.
Which circuit component is represented by the following diagram?
Light Dependent Resistor
What is the rule for voltages in a series circuit?
The voltage across each component added together is equal to the supply voltage.
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.
What type of current is represented by this oscilloscope image?
DC
What is the energy change in an LED?
Electrical to light