Perfect Answers to Revise

Check out this list of nearly 200 perfect answers from common questions taken from SG, Int 1, Int 2 and N5 Marking instructions. Why not work with some friend and make up some flashcards and see who can get most right in a given time.

QuestionResponse
State the purpose of the fuse fitted in the plug of an appliance.stops too large a current
OR prevents wiring overheating
OR protect wiring (from damage)
Explain in terms of electron flow what is meant by alternating current.direction of electron (flow)
(continually) changing back and forth/to and fro
What happens to the power when the when R added in parallel?(power dissipated is) greater/increased/higher (combined/parallel/total) resistance less voltage across motor is greater/increased OR current (in motor) is greater/increased
Using the kinetic model, explain what happens to the pressure of the air inside the pump as its volume decreases.(individual) particles collide with container/walls more frequently (than before) (overall) force (on walls) is greater pressure increases
Suggest how the accuracy of the frequency determined by the student could be improved.measure the time for more waves to pass
OR count the number of waves in a longer period of time
OR repeat (the measurement) and average
State what is meant by an activity of 80 kBq.80 000 (nuclei) decay(s) per unit time
Explain how a single reaction can lead to the continuous generation of energy.neutrons can go on to cause further (fission) reactions/split more (uranium) nuclei causing a chain reaction/this process repeats
Use of NUCLEAR RADIATIONany suitable use (eg treating cancer/tracers/ sterilisation/smoke detectors/ measuring thickness of paper)
Describe how the upward force exerted by the weightlifter on the barbell compares to the weight of the barbell.(The forces are) equal (in size) and opposite (in direction).
State a suitable detector of visible lightphotographic film
State the speed of the radio waves.3.00 ´ 10 8 ms -1
State what is meant by the term gamma rays.High frequency (or short wavelength) electromagnetic radiation
The radioactive source must be stored in a lead-lined container.
Explain why a lead-lined container should be used.
Lead can absorb (some of) the gamma rays
State the annual effective dose limit for the radiation worker.20 mSv
Explain why the phone receives a signal at X but not at Y.The waves from the transmitter will diffract over the hill to reach X but will not diffract enough to reach Y
Using the kinetic model, explain the increase in the pressure of the gas in the syringe as its volume decreases.As volume decreases, the particles of gas will strike the piston of the syringe more often Since P= F/A , this results in an increased pressure
Explain how the graph confirms that Xis directly proportional to Y.The line of best fit is a straight line
which passes through the origin
Explain how this [ LDR Mosfet ] circuit worksLight level increases, LDR resistance decreases
LDR resistance decreases, voltage across R increases
Voltage across R increases, MOSFET switches the motor on
State how the frequency of microwave radiation compares to the frequency of infrared radiation.(Microwave radiation has a) smaller (frequency than infra-red radiation)
State whether the orbital period of the ISS in its highest orbit will be less than, the same as, or greater than the orbital period calculated in part (d) (i).(Orbital period will be) greater
Explain, in terms of forces, how the parachutes reduce the speed of
the Module.
Upward force is increased (by parachutes) producing an unbalanced force upwards
Explain why these Modules burn up on re-entry into the atmosphere.Force of friction is created on the surface of the modules causes heat to be produced
Explain why in hilly regions you can receive radio but not TV signalsRadio waves are longer in wavelentgh than TV waves and longer waves diffract more than waves with a shorter wavelength
State the speed of microwave signals in air3 x 10⁸ m/s or 300,000,000m/s
What is meant by the term geostationaryOrbits at 36000km above the equator OR same period as earth
State a reason for a commercial motor using field coils instead of permenant magnetsMotor has a smaller mass OR field can be controlled OR can be used in AC/DC OR can be switched off
State a reason for a commercial motor using a multi section commuter instead of a single commuterMotor is more powerful OR turns more smoothly
A student has an eye defect. An object close to the students eye appears focoused but a distant object appears blurred. What name is given to this eye defect?Myopia or short sight
State what is meant by thr term ionisationWhen an atom gains negative charge OR when an atom loses negative charge. OR when an atoms gains electrons OR when at atom loses electrons
State the unit of equivalent dosesieverts/Sv OR mSv
Suggest a suitable output that will illuminate the warning display (on a car)LED
Explain in terms of forces, why seatbelts are used in carsThe driver will continue to travel at a constant speed until the seatbelt applies an unbalanced force to stop the driver
The temperature outside the car is measured with an electronic thermometer and displayed on a screen. What input device could be used in the electronic thermometer?_x000D_
OR gate
State what is meant by gravitational field strengthWeight per unit mass
Which radiation in the EM spectrum has the shortest wavelengthGamma
State one detector of radio wavesThermograms OR electronic thermometer
Describe how signals are transmitted along optical fibres.(Light travels through the glassfibre.) Rays of light are(totally internally) reflected
(inside the fibre) OR: “TIR”
State one advantage of using optical fibres rather than copper wires for transmitting signals.Carry more information OR
better signal quality
Explain why the mains switch must be connected to the live cable from the mains supply.To switch off all circuits OR To isolate the consumer unit fuses and domestic circuits from the mains supply
State another difference between the ring circuit and the lighting_x000D_
circuit.
The lighting circuit uses thinner
cable
State one advantage of using a ring circuit as a preferred method of wiring in parallel.Two routes for current to flow/less
(half) current in each branch
OR
Thinner cable/cheaper
1 Accept:
 Easier to add more sockets
 Less heating
 Less voltage drop
DO NOT accept:
 Safer (unless qualified by “less current”)
 Less cable
 Any comparison with series circuit
 Less current per ring
 All sockets get 230 V
State one advantage of using a circuit breaker instead of a fuse.Reusable/faster response time/
easily reset
1 Accept:
 Easier to tell if on or off
 ‘Trips’ at a smaller overload
 Fuse needs to be replaced
 Switches off “immediately”
DO NOT accept:
 Cheaper
State one further safety precaution that should be taken by the teacher when handling the radioactive sources.Use forceps/don’t point at eyes/
wear gloves etc
Describe one medical use of radiation where the radiation is used to destroy cells.Instrument sterilisation/treatment of_x000D_
cancer
Explain how this circuit operates to activate the motor in the dryer when the light level falls below a certain value.R of LDR increases (½) V across LDR increases_x000D_
(above 0·7V) (½)_x000D_
Transistor switches ON (½)_x000D_
Relay coil is energised_x000D_
(which closes the relay switch_x000D_
and activates the motor) (½)
Name a suitable output device that could be used in the alarm box to produce an audio output.When one of the inputs_x000D_
(to gate X) is logic 0/OFF/_x000D_
LOW (½)_x000D_
The output (from gate X) is_x000D_
logic 0/OFF/LOW_x000D_
(½)
Explain, in terms of Newton’s Third Law, how the rocket engines propel the rocket upwards.Engine/exhaust gases pushed down_x000D_
(A on B); gases push rocket up_x000D_
(B on A)_x000D_
Explain why larger aircraft require a longer runway to land safely.Aircraft has increased mass 1_x000D_
so has reduced deceleration 1_x000D_
OR_x000D_
Aircraft has increased kinetic energy 1_x000D_
w E = Fd (so if F is constant d is greater) 1
Explain why these Modules burn up on re-entry into the atmosphere.Force of friction is created on the_x000D_
surface of the modules 1_x000D_
causes heat to be produced 1
Explain, in terms of forces, how the parachutes reduce the speed of the Module.Upward force is increased (by_x000D_
parachutes) 1_x000D_
producing an unbalanced force_x000D_
upwards
Explain, in terms of its horizontal velocity and weight, how the ISS remains in orbit around the Earth.The horizontal velocity of the ISS is_x000D_
large enough to ensure that it does_x000D_
not get closer to the Earth’s_x000D_
surface (or equivalent statement) 1_x000D_
The weight of the ISS is large_x000D_
enough to ensure that it does not_x000D_
move further away from the Earth’s_x000D_
surface (or equivalent statement) 1
State how the frequency of microwave radiation compares to the frequency_x000D_
of infrared radiation.
(Microwave radiation has a) smaller_x000D_
(frequency than infra-red radiation)
The MOSFET switches on when the voltage across variable resistor R reaches 2·4 V. Explain how this circuit works to close the blind.Light level increases, LDR_x000D_
resistance decreases 1_x000D_
LDR resistance decreases, voltage_x000D_
across R increases 1_x000D_
Voltage across R increases,_x000D_
MOSFET switches the motor on 1
Explain why the actual time taken to make the ice will be longer than the time calculated in part (c) (i).Heat will be taken in from the_x000D_
surroundings 1_x000D_
so the system will have additional_x000D_
heat to remove 1
Using the kinetic model, explain the increase in the pressure of the gas in the syringe as its volume decreases.As volume decreases, the particles_x000D_
of gas will strike the piston of the_x000D_
syringe more often 1_x000D_
Since P= F/A , this results in an_x000D_
increased pressure 1
When carrying out the experiment, the student clamped the syringe rather than holding it in their hand._x000D_
Explain why this is better experimental practice.
Using a clamp will prevent heat_x000D_
from the student’s hand increasing_x000D_
the temperature of the gas in the_x000D_
syringe 1_x000D_
If the temperature of the gas in the_x000D_
syringe is not constant, the_x000D_
experiment would not be valid 1
A second student suggests that replacing the short tubing between the syringe and the pressure sensor with one of longer length would improve the experiment._x000D_
Explain why this student’s suggestion is incorrect.
The suggestion is incorrect because_x000D_
the volume of air in the tubing is_x000D_
not being read from the scale on_x000D_
the syringe 1_x000D_
A longer length of tubing would_x000D_
increase the (systematic)_x000D_
uncertainty in the experiment 1
The climber also carries a mobile phone. The climber notices that the phone receives a signal at X but not at Y._x000D_
Explain why the phone receives a signal at X but not at Y.
The waves from the transmitter will_x000D_
diffract over the hill to reach X 1_x000D_
but will not diffract enough to_x000D_
reach Y 1
Explain why this method (half-life) could not be used to estimate the age of a tree that died 100 years ago.The activity (of a sample from the tree)_x000D_
would not have reduced significantly/_x000D_
measurably in 100 years
AnswerQuestion
(As orbit is circular) direction changes / or unbalanced force exists so velocity changes .Although the satellite travelled at a constant speed in a circular orbit, it accelerated continuously. Explain this statement._x000D_
Car continues at a constant speed during this time. AB represents driver’s reaction time OR the forces are balanced (orequivalent).Describe and explain the motion of the car between A and B.
Less than. Some heat is lost to surroundings.Is the actual temperature change of the ball greater than, the same as or less than the value calculated in part (a)(ii)? You must explain your answer.
Answer= 3.42 This is greater than the 3W or labelled power rating (so it overheats).During this experiment, the resistor becomes very hot and gives off smoke. Explain why this happens
No. In parallel the voltage is still the same/6V across each resistor so its power is the sameThe student states that two of these resistors would not have overheated if they were connected together in parallel with the battery._x000D_
Is the student correct? explain your answer_x000D_
As the temperature increases the resistance of thermistor RT decreases. What happens to the voltage across RT as the temperature increases?Voltage falls/decreases
The temperature of RT now decreases.
Will the lamp stay on or go off?
You must explain your answer.

Temperature decreases, resistance increases, voltage drop increases to be >2.4V. Circuit switches on.
A student standing beside the apparatus observes the beeps and flashes happening at exactly the same time. Another student 88 m away does not observe them happening at the same time.The speed of sound is less than the speed of light.
Optical fibres are used to carry internet data using infra-red radiation. Is the wavelength of infra-red radiation greater than, the same as, or less than the wavelength of visible light?Greater
The diagram shows the path of the infra-red ray as it passes through a section of the fibre, name the effect shown.
Total Internal Reflection
More amplitude recieved at the microphoneExplain why using the curved reflector makes the sound detected by the_x000D_
microphone louder.
Short sightedness The spy needs spectacles to see distant objects clearly._x000D_
What is the name given to this eye defect?
What type of lens is needed to correct this defect (short sightedness?convcave
weapons, rocks, atmosphereState two factors which can affect the background radiation level.
A type of electromagnetic radiation / wave/ ray. The source emits gamma rays. State what is meant by a gamma ray.
The moderator slows neutrons.In a nuclear reactor, state the purpose of:_x000D_
the moderator
The containment vessel prevents/reduces release of_x000D_
radiations OR radioactive gases OR radioactive substances etc.
the containment vessel.
Fission or Chain reaction.What type of nuclear reaction takes place in a nuclear power station’ s reactor?
The accepted value for the density of air at this temperature is 1·29 kg m–3. Explain why the technician’s answer is different from the accepted value.Not all the air will be evacuated from jar OR It is impossible to get a perfect vacuum OR Some air has leaked back in
Use the kinetic model to explain this change in pressure after removing air with the syringe.Particles collide with walls of jar. Number of collisions on walls of jar is less frequent. Average force (on walls) decreases. Pressure on walls of jar decreases
Explain why the reading on the voltmeter has decreased(Total) resistance decreases (circuit) current increases, lost volts increases
Explain what is meant by a capacitance of 200 µF.200 µC of charge increases voltage across plates by 1 volt OR 200 µC per volt OR One volt across the plates of the capacitor causes 200 µC of charge to be stored
The distance between the two foils is now increased and the experiment repeated. Explain why this gives a more accurate result for the acceleration due to gravity.Percentage fractional uncertainty in measuring distance will be smaller OR percentage fractional fractional uncertainty in measuring time will be smaller
Explain why the output voltage Vo does not increase above 13 V.output cannot be greater than approx 85% of the supply voltage OR saturation of the amplifier has been reached
Explain why the kinetic energy of the electrons is zero below the frequency f₀Photons with frequency below f₀ “because f₀ is threshold do not have enough energy to release electrons OR Photons with frequency below f₀ have energy smaller than work function
gamma radiation can penetrate the body OR as beta radiation cannot penetrate the bodyExplain why Iodine-123 should be used as a tracer to diagnose problems in the thyroid gland.
 (As temp increases,) input voltage to transistor increases (½)  (above 0·7V) switching transistor on (½)  Current in the (relay) coil (producing magnetic field). (½)  (Relay) switch closes / activates, (½) (completing the bell circuit/ operating the bell).Explain how the circuit operates to sound the bell when the temperature of the thermocouple reaches a certain value.
Energy is lost as sound OR heat (within the transformer coils/core.)State one reason why transformers are not 100% efficient.
It moves with constant speed in the horizontal direction (1) while accelerating due to the force of gravity in the vertical direction (1)The ISS orbits at a height of approximately 360 km above the Earth. Explain why the ISS stays in orbit around the Earth.
direction of electron (flow) (continually) changing back and forth/to and froThe blender is connected to an alternating current (a.c.) supply. Explain in terms of electron flow what is meant by alternating current.
(power dissipated is) greater/increased/higher (1) (combined/parallel/total) resistance less (1) voltage across motor is greater/increased OR current (in motor) is greater/increased (1)State the effect that closing switch S2 has on the power dissipated in the motor. Justify your answer.
(individual) particles collide with container/walls more frequently (than before) (1) (overall) force (on walls) is greater (1) pressure increases (1)Using the kinetic model, explain what happens to the pressure of the air inside the pump as its volume decreases.
The rocket engine in a spacecraft burns fuel producing exhaust gases. Identify the Newton pair of forcesThe spacecraft (or equivalent) pushes the exhaust gases (backward). The gases push the spacecraft (or equivalent ) ( forward.)
State the energy transformation in the filament lamp.Electrical ---> light + heat
Filament lamps and LEDs are examples of output devices. Name one other output device. Any suitable – heater, motor, (loud)speaker, relay, etc.
Explain in terms of electron flow what is meant by alternating current (a.c.).The flow of electrons constantly changes direction
Explain why the guitar string induces an a.c. voltage.The string changes direction (in the magnetic field.)
Name the effect used to transmit light through a glass optical fibre.Total internal reflection
The worker wears a badge containing photographic film. Explain how this can indicate if the worker has been exposed to radiation.Photographic film will) fog / darken (when exposed to radiation).
X-rays can cause ionisation. Explain what is meant by ionisation.When an atom gains / loses (orbiting) electrons.
Use the kinetic model to explain what happens to the pressure of the gas as its temperature decreases. as temperature decreases the particles slow down/lose Ek . strike the sides of the container less often. each collision less forceful/hard. pressure decreases. Reference must be clearly about the force of the individual particle collisions eg “the particles move more slowly and so strike the walls less often, meaning the force is less and so the pressure is less”
Using the terms electrons, holes and photons, explain how light is produced at the p-n junction of the LED.(When the LED is forward biased) holes and electrons (re)combine (at the junction ) (of the LED) and photons (of light) are produced/emitted.
Explain why a spectrum is produced in the glass prism.Different frequencies / colours are refracted through different angles OR different frequencies / colours have different refractive indices
State what is meant by the resultant of a number of forces.A single force which will have the same effect as all the other forces
The parascender releases the rope and initially rises higher. Explain, in terms of the forces acting, why the parascender rises.The vertical component of the force exerted by the parasail is greater than the weight of the parascender.
Explain what happens to the density of the trapped air when its temperature is increased.remains the same neither the mass nor the volume have changed
Capacitors have an insulator between their plates. Explain why there is a current in the circuit during the charging process.Electrons flow in all the wires because they are repelled from negative terminal of power supply to bottom/one plate of the capacitor and they are attracted off the top/other plate towards positive terminal of power supply
At the end of the run, the engine is switched off and parachutes attached to the car slow it down. Explain how the parachutes slow down the car.Parachute creates friction (which acts in opposite direction to motion)
Explain the difference between conductors and insulators.Conductors allow charges to move and insulators do not
Explain what a.c. and d.c. mean in terms of current.a.c. − Current changes direction continuously (1) d.c. − Current is in one direction
Is the wavelength of the ultrasound in the tissue longer, shorter or the same as it is in air? Explain your answer.Longer (1) frequency same but velocity greater
Which radioactive source should be used? You must explain your answer Source X: (1) beta is required (owing to the range/some of it would be absorbed by the paper) (½) with a long half-life
Explain the function of the moderatorslows neutrons
In practice the acceleration is not constant. Give a reason for this.Other forces will act on the plane, mass decrease
State the speed of ultrasonic waves in air340 m/s
What happens to the lost kinetic energy?Turns into heat energy
State what is meant by the term voltage. (The voltage of a supply is a measure of) the energy given to the charges in a circuit.
State how this affects the speed of the motor compared to Circuit 1. Explain your answerThe motor speed will reduce. The (combined) resistance (of the circuit) is now higher/current is lower. Voltage across motor is less Motor has less power
What is the purpose of component X in the circuit?To act as a switch
What is the purpose of the variable resistor R in this circuit?The variable resistor is to set the light level at which the transistor will switch on or to set the level at which the buzzer will sound
Light waves are transverse waves. Sound waves are longitudinal waves. Describe each type of wave in terms of vibrations.With transverse waves the vibrations are at right angles to the direction of travel. With longitudinal waves the vibrations are in the same direction of travel.
State what is meant by a radiation weighting factor.A measure of the biological effect of a radiation.
Disposal of some types of radioactive waste from nuclear reactors is particularly difficult. Give a reason for this difficulty.Stays (highly) radioactive for a (very) long time
Another student carries out the same experiment using a flask of larger volume. Explain why this is a better design for the experimentA flask of larger volume is better because this increases the mass and volume of air and used in the experiment. This should result in a smaller percentage error in the measurements of both mass and volume of the gas. This will in turn reduce the percentage error in the calculated density of air.
Use the kinetic model to explain what happens to the pressure of trapped air if its volume increases.Pressure is caused by the gas particles exerting a force on the walls of the container. When the volume of the container decreases there is an increase in the collision rate, meaning that more force is exerted on the container walls. This increases the pressure as pressure is a measure of force per unit area (P = F/A).
What change could be made to this circuit to ensure that the same capacitor stores more energyIncreasing the supply voltage would increase the energy storing capacity of the capacitor. This is because the final voltage, across the fully charged capacitor, would be higher.
In a laser the light is produced by stimulated emission of radiation. Explain the term 'stimulated emission' by making reference to the energy levels in atoms A high voltage or other energy source can be used to pump electrons up into higher energy states. For example, an electron can be pumped up to energy level (E2) and then fall into the metastable state E1, creating what is called an inverted population. A passing photon, having an energy equal to the energy gap E1 to E0 can encourage/stimulate an electron to drop from energy state E1 to E0 with the production of a photon in phase, with the same frequency and travelling parallel to the stimulating photon. Thereafter, photons produced by stimulated emission can cause further stimulated emission. This is the basis for stimulated emission and amplification.
The distance between the screen and the laser is now doubled. State how the radius of the spot now compares with the one shown in the diagram. You must justify your answerThe laser beam is non divergent. It does not spread out. This means the radius of the spot is a constant.
Two 15kg masses, X and Y, shaped as shown, are dropped through the same distance on two identical uncovered concrete pipes. When the masses hit the pipes, the masses are brought to rest in the same time. Which mass causes more damage to a pipe? Explain your answer in terms of pressureBlock X will cause more damage because the force, although the same for each block, is exerted over a smaller area. This results in more pressure applied to the pipe. Pressure = Force/Area
In the circuit above, the 20 ohm resistor is now replaced with a 10 ohm resistor. The intensity of light is unchanged. The following measurements re obtained.S closed =0.011V. S open= 0.508V. Explain why the reading on the voltmeter, when S is closed is smaller than the corresponding reading in part (b)Decreasing the value of the load resistor will increase the current in the circuit. This will increase the "lost" volts (Vlost=Ir). Voltmeter reading = emf-Vlost This explains the lower reading on the voltmeter when the switch is closed.
Explain why, as angle x is unchanged, it is important to keep the lightmeter at a constant distance from point X for each measurement of intensity.By keeping the light meter a constant distance from X you are justified in stating that any change in the recorded intensity is a result of changing q. If the distance was altered a change in intensity could be the result of a diverging beam.
Explain what is meant by photoelectric emission from a metal.Photoelectric emission is the term used to describe the process by which an electron bound in an atom can absorb enough energy from a single photon to escape, or be emitted, from the atom.
Explain why the actual temperature rise of the disc is less than
calculated in (b) (i).
energy is lost to the surrounding air
State which, if any, of the resistors will overheat30 ohm resistor will overheat
The 9V d.c. supply is replaced by a 9V a.c. supply.
What effect, if any, would this have on your answers to part (b) (ii)?
none
What energy change takes place in the microphoneSound energy to Electrical energy
The amplifier processes the signal from the microphone.
What effect does the amplifier have on the signal’s
(i) frequency;
 (ii) amplitude?
(i) None
(ii) Greater
Explain what is meant by the term “critical angle”.If light inside the prism strikes the surface at an angle greater than the critical angle it will be totally internally reflected.
Explain how this circuit works to close the blind.The resistance of LDR drops
(with light level rise)
V across R rises
until MOSFET switches on the motor
What is the purpose of the variable resistor R?to set the light level at which the blind closes.
State whether or not the blinds will close when the light level is

Since V< 2·4 V transistor will not switch on
so blinds do not shut.
Why does each LED need a resistor in series?to limit current in/voltage across the LED
What type of lens should be used?Converging/convex
How would the shape of this lens have to be altered to give it a longer focal
length?
Make thinner/or less curved
Name the eye defect which this type of lens could correctLong sight
The radioactive source and detector are moved along the weld. How
would the count rate change when the detector moves over an air pocket?
Explain your answer.
Count rate increases
Air is more easily penetrated/less metal to be penetrated
Which of the radiations alpha, beta or gamma must be used?
Explain your answer.
Gamma penetrates best/other two would not penetrate steel
X-rays are sometimes used to detect air pockets.How does the wavelength of X-rays compare with gamma rays?x-rays longer/gamma shorter
What is meant by the term “half-life”?time taken for half of the radioactive atoms to decay or activity to decrease by half
Describe two precautions taken by the scientists to reduce the equivalentdose they receive while using radioactive sourcesAny 2 of shielding/limiting time of exposure/ increasing distance


The risk of biological harm from radiation exposure depends on theabsorbed dose and the type of radiation. Which other factor affectsthe risk of biological harm?Tissue type
Speed at Q is greater, Mass of car is greater, Deceleration is less Since a = F/m (and F is constant) Can gain full marks by calculation Test repeated, same car but with passegers. Speed at P still 30 m s–1. Same braking force. How does the speed of the car at Q compare?
What effect, if any, does this decrease in temperature have on the density of the oxygen in the cylinder?
No change
both mass and volume remain
constant
Fewer molecules/atoms/particles inside canister so fewer collisions/hits with
walls per second 
Temp of oxygen inside cylinder remains constant. Explain, in terms of particles, why pressure of the gas inside the cylinder decreases.
When in use, internal resistance of each cell gradually increases.
What effect, does this have on the power output of the heating
element?
Power output is less ½               Current is less        RIP 2 =   R (load) is constant
State what is meant by the term capacitance.Quantity of charge stored per volt
Yellow LED is lit _x000D_
Because it is forward biased
Which LED(s) is/are lit at this value of output voltage?_x000D_
Justify your answer.
State what is meant by an activity of 12 kBq.12000 decays per second
0·03 µSv State the average equivalent dose received by the hand on each
occasion. 0.030 μGy
State whether the speed of ultrasound in brass is less than, equal to or greater than the speed of ultrasound in steelThe speed of ultrasound is brass is less than it is in steel (1) AND it takes a longer time to travel the same distance (1)
State what happens to the speed of the light as it enters a diamondIt decreases/slows down
State what is meant by the term half-lifeTime taken for activity to decrease by half OR time taken for half of the nuclei to decay
State what is meant by a gamma rayAn EM wave/a high frequency electromagnetic wave
Describe the energy change that takes place as the marble (is dropped) and hits the sandkinetic energy to heat and sound energy
Define the term acceleration.Acceleration is the change of velocity (not speed) in unit time
Explain how the satellite can be accelerating when it is travelling at a constant speed.Direction of satellite is (continually) changing
Gamma radiation is an example of radiation which causes ionisation. Explain what is meant by the term ionisation.Ionisation is when an atom gains or loses electrons
The accepted value for the specific heat capacity of water is quoted in the table in the Data Sheet. Explain the difference between the accepted value and the value obtained in the experiment.Measured value of ܧ୦ too large OR Δ T too small
How could the experiment be improved to reduce this difference?Insulate beaker
Which power supply should be used to operate the transformer?ac OR mains OR one on left
What is the purpose of a transformer?Transformers are used to change* the magnitude † (size ok) of an (alternatin g) volta ge OR current
What is the purpose of resistor R?To reduce current in LED
State the energy change in a solar cellLight → electric (al) Not ‘electricity’
Identify radiations P and Q.P – Ultraviolet OR UV,Q – Microwaves
State what happens to the frequency of electromagnetic radiation as the wavelength increases.Decrease/reduces/goes down/lessens
Carbon-14 emits beta particles. What is a beta particle?An electron
A radioactive source emits alpha particles. What is an alpha particle?A helium nucleus OR equivalent eg 2p + 2n
How does the ionisation density of alpha particles compare with that of beta particles?Greater Stronger -0 More powerful -0
One of the lamps now develops a fault and stops working. State the effect this has on the other lamp. You must justify your answer.The other lamp: remains lit, stays on, is the same brightness, gets brighter, is not affected. Justification: The current still has a path through the other lamp. (1)

OR

The current in the other lamp is the same (only acceptable if other lamp stays same brightness) (1)
Explain how the circuit operates to switch on the heater when the temperature falls below a certain value.
(As Rth increases,) Vth increases (1)
(When Vth = 2·0 V or V reaches switching voltage,) MOSFET/transistor turns on (1)
Relay switches on (the heater). (1)
The resistance of the variable resistor R is now increased. What effect does this have on the temperature at which the heater is switched on? You must justify your answer.
Temperature decreases (1)

Resistance of thermistor must be greater / increase (1)

to switch on MOSFET / transistor (1)
X-rays can cause ionisation. Explain what is meant by ionisationWhen an atom gains / loses / gains or loses electrons.
The pilot and passengers are weighed before they board the helicopter. Explain the reason for this.
To check that the maximum takeoff weight is not exceeded.
The student launches the rocket a second time. For this launch, the student adds a greater volume of water than before. The same initial upward thrust acts on the rocket but it fails to reach the same height. Explain why the rocket fails to reach the same height.
more water will increase weight/mass (1) unbalanced force decreases (1)
acceleration is less (1)
3 x 10⁸ m/s

Learn these Experiment

Thanks to S Gray, Drummond Community High School,  for putting together this book of experiments that you should have covered in your N5 Physics lessons. Any of these could be discussed in your exam as a question.


Required Experiments v3

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Practice Questions

Thanks to the wonderful Physics teacher who provided these.

Dynamics & SpaceElectricity & EnergyWaves & Radiation
Notes ver 1.2 doc
Notes ver 3.1Notes ver 2.1
Problems 1.2 docProblems 3.0 docProblems 3.1 doc

Problems 1.2 pdfProblems 3.0 pdfProblems ver 3.1 pdf
Answer File ver 1.4 Answer File ver 3.0Answer File ver 3.1

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SPACE

Mrs Physics and Ms Horn are working on the last unit for the N5 course- the new Space Topic.
There have been several changes from the previous outcomes. This ought to be the most up to date work.



You can read about some of the risks of human spaceflight in the infographic below.

Infographic: Some of the most harrowing space disasters that have occurred.


Source Space.com: All about our solar system, outer space and exploration

Here are a few links and documents. Hope you can get access to them.

www.open.edu/History of Universe Timeline

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Revision Questions

Thanks to those in North Ayrshire who provided these excellent questions for you to get your teeth into. I’ll post the answers as password protected to protect those students and staff who are given these for homework! They’re in the old order, so you’ll have to search through for the right section.

ENJOY!

UnitsSummary NotesProblems
Dynamics & SpaceSummary Notes D&SQuestions D&S pdf
Problems D&S doc
Electricity & EnergySummary Notes E&EQuestions E&E pdf
Problems E&E doc
Waves & RadiationSummary Notes W&RQuestions W&R pdf
Problems W&R doc

 

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Quantity Symbol, Unit and Unit Symbol

I’ve put together, with Mrs Mac’s help, a document with quantity, symbol, unit and unit symbol so that you know the meaning of the terms in the Relationships Sheet. It is in EXCEL so that you can sort it by course, quantity or symbol.

Quantity, Symbol, Units  the excel sheet

Quantity, Symbol, Units N5 a pdf sheet sorted by course and then alphabetical by quantity.

Quantity, Symbol, Unit, Unit Symbol N5-AH

NHAPhysical Quantity symUnitUnit Abb.
5absorbed dose D gray Gy
5absorbed dose rate H (dot)gray per second gray per hour gray per year Gys-1 Gyh -1 Gyy-1
567acceleration a metre per second per second m s-2
567acceleration due to gravity g metre per second per second m s-2
5activity A becquerel Bq
567amplitude A metre m
567angle θ degree °
567area A square metre m2
567average speedv (bar)metre per second m s-1
567average velocity v (bar)metre per second m s-1
567change of speed ∆v metre per second m s-1
567change of velocity ∆v metre per second m s-1
5count rate - counts per second (counts per minute) -
567current I ampere A
567displacement s metre m
567distance dmetre, light year m , ly
567distance, depth, height d or h metre m
5effective dose H sievert Sv
567electric charge Q coulomb C
567electric charge Q or q coulomb C
567electric current I ampere A
567energy E joule J
5equivalent dose H sievert Sv
5equivalent dose rate H (dot)sievert per second sievert per hour sievert per year Svs -1 Svh-1 Svy -1
567final velocity v metre per second m s-1
567force F newton N
567force, tension, upthrust, thrustF newton N
567frequency f hertz Hz
567gravitational field strength g newton per kilogram N kg-1
567gravitational potential energy Epjoule J
5half-life t1/2 second (minute, hour, day, year) s
56heat energy Eh joule J
567height, depth h metre m
567initial speed u metre per second m/s
567initial velocity u metre per second m s-1
567kinetic energy Ek joule J
567length l metre m
567mass m kilogram kg
5number of nuclei decayingN - -
567period T second s
567potential difference V volt V
567potential energy Ep joule J
567power P watt W
567pressure P or p pascal Pa
5radiation weighting factor wR- -
567radius r metre m
567resistance R ohm Ω
567specific heat capacity c joule per kilogram per degree Celsius Jkg-1 °C -1
56specific latent heat l joule per kilogram Jkg -1
567speed of light in a vacuum c metre per second m s -1
567speed, final speed v metre per second ms -1
567speed, velocity, final velocity v metre per second m s-1
567supply voltage Vsvolt V
567temperature T degree Celsius °C
567temperature T kelvin K
567time t second s
567total resistance Rohm Ω
567voltage V volt V
567voltage, potential difference V volt V
567volume V cubic metre m3
567weight W newton N
567work done W or EWjoule J
7angle θ radian rad
7angular acceleration aradian per second per second rad s-2
7angular displacement θ radian rad
7angular frequency ω radian per second rad s-1
7angular momentum L kilogram metre squared per second kg m2 s -1
7angular velocity,
final angular velocity
ω radian per second rad s-1
7apparent brightnessbWatts per square metreWm-2
7back emfevolt V
67capacitance C farad F
7capacitive reactance Xcohm W
6critical angle θc degree °
density ρ kilogram per cubic metre kg m-3
7displacement s or x or y metre m
efficiency η - -
67electric field strength E newton per coulomb
volts per metre
N C -1
Vm -1
7electrical potential V volt V
67electromotive force (e.m.f) E or ε volt V
6energy level E 1 , E 2 , etcjoule J
feedback resistance Rfohm Ω
focal length of a lens f metre m
6frequency of source fs hertz Hz
67fringe separation ∆x metre m
67grating to screen distance D metre m
7gravitational potential U or V joule per kilogram J kg-1
half-value thickness T1/2 metre m
67impulse (∆p) newton second
kilogram metre per second
Ns
kgms-1
7induced e.m.f. E or ε volt V
7inductor reactanceXLohm W
7initial angular velocity ω oradian per second rad s-1
input energy E ijoule J
input power Piwatt W
input voltage V 1 or V2 volt V
input voltage V ivolt V
6internal resistance r ohm Ω
67irradiance I watt per square metre W m-1
7luminoscityLWattW
7magnetic induction B tesla T
7moment of inertia I kilogram metre squared kg m2
67momentum p kilogram metre per second kg m s-1
6number of photons per second per cross sectional area N - -
number of turns on primary coil n p- -
number of turns on secondary coil n s- -
6observed wavelengthλ observedmetrem
output energy E o joule J
output power P owatt W
output voltage V o volt V
6peak current Ipeak ampere A
6peak voltage V peak volt V
7phase angle Φ radian rad
67Planck’s constant h joule second Js
7polarising angle
(Brewster’s angle)
i pdegree ̊
power (of a lens) P dioptre D
power gain Pgain - -
7Power per unit areaWatts per square metreWm-2
primary current I p ampere A
primary voltage Vpvolt V
7radial acceleration ar metre per second per second m s-2
6redshiftz--
67refractive index n - -
6relativistic lengthl'metrem
6relativistic timet'seconds
rest mass mo kilogram kg
6rest wavelengthλrestmetrem
6root mean square current I rmsampere A
6root mean square voltage Vrmsvolt V
7rotational kinetic energy Erotjoule J
7schwarzchild radiusrSchwarzchildmetrem
secondary current Is ampere A
secondary voltage Vsvolt V
7self-inductance L henry H
67slit separation d metre m
7tangential acceleration atmetre per second per second m s-2
6threshold frequency fohertz Hz
7time constanttseconds
7torque Τ newton metre Nm
7uncertainty in Energy∆E jouleJ
7uncertainty in momentum∆px kilogram metre per second kgms-1
7uncertainty in position∆x metre m
7uncertainty in time∆t seconds
6velocity of observer vometre per second m s-1
6velocity of source vsmetre per second m s-1
voltage gain - - -
voltage gain Ao or V gain - -
567wavelengthλmetrem
6work functionWjouleJ

 

Revision for..

Revision Plan – 2018/9

A revision planner for you to use. Revision-plan 2018 19

Revision-plan 2018 19

Someone has pinched my line!

and I had this idea at Science on Stage!

www.iop.org/physics-songs

For those doing the UASP -Electricity and Energy

  • Revise the type of energy and conversion
  • Gravitational potential
  • Kinetic
  • Work done
  • Heat
  • Electrical
  • Practical electrical and electronic circuits
  • Ohm’s law
  • Electrical practical circuits
  • Electrical power
  • Specific Heat Capacity
  • Pressure
  • Gas Laws
  • Kinetic Theory

Try the following questions

Specimen Paper:

Section 1:    q6, 10, 11, 12, 13,14,15,16,17, Section 2:        Q5, 6, 7, 8

National 5 2017

Section 1: Q1-7, 19,         Section 2: Q1,2,3,

National 5 2016

Section 1: Q1-7      Section 2: Q1,2,3,4,5

National 5: 2015

Section 1: Q1-6      Section 2: Q1,2,3,4

National 5: 2014

Section 1: Q1-7      Section 2: Q1,2,3

 

Learn the formula for

Ew=QV, Ew=Fd,    Ep=mgh,     Ek=½mv2,     E=Pt,      Ee=ItV, EH=mcΔT,           EH = ml,            P=F/A,        Q=It,       R in series,        R in parallel, V1 =R1/Rt ´Vs,     V=IR,     P=IV,     P=I2R,     P=V2/R, pV/T(K)=constant

Make flashcards of

  • The Kinetic theory
  • Gas Laws
  • Rules for series and parallel
  • Circuit Symbols
  • Rules for charges attracting and repelling
  • Definitions of
    • Pressure
    • Temperature and average speed and kinetic energy
    • Electric Fields
    • Conservation of Energy
    • Specific Heat Capacity
    • Specific Latent Heat
    • Power
    • Current

Learn the units for all the electricity quantities, properties of matter and energy quantities.

I’ll add to this during the week as I have time

If you are doing a PROPERTIES OF MATTER TEST

Look over some OLD Higher papers for the Pressure and Gas Laws as well as the relevant past papers above. I’ll look out the papers with question numbers as soon as I can.

If you’re doing the Waves and Radiation UASP I’ll get some revision plans up soon

Old/ traditional higher……

H 2015 Q7 and 24

H 2014 Q7 and 24

H 2013 Q7 and 24 not part c

H2012 Q7 and 24

H 2011 Q7 and 24

H 2010 Q7 and 23 b

H 2009 Q7 and 23 a,c

H 2008 Q7 and 23

These can be found on the higher part of the website.

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Updated July 18


Interpreting graphs

A few folk have worried that they can’t interpret graphs, so I’ve gone through some SG Credit Papers and written a few questions. You can answer the past paper questions. I’ll  upload the answers when I’ve done them!

Interpreting Graphs pdf

Interpreting Graphs word

SG past paper questions and answers

 
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Homework N5 Starters

Currently this is homework for the S3 Pro Physics Class- but N5 might be asked to research this too.

National 5 PHYSICS Assignment starters

Answer the following Questions from the Understanding Standards website

https://www.understandingstandards.org.uk/Subjects/Physics

It is important that you spend an adequate time on this homework (an hour is advised). If you complete this thoroughly you ought to have a good grasp of what is required for the Assignment at National 5.

  1. List the twelve experiments that have been given as examples for the N5 Physics Assignment.
  2. In the marking instructions for the assignment how many marks are available for the underlying Physics?
  3. What are the four sections in the data collection and handling (and I don’t want 4a, 4b, 4c and 4d!)
  4. Section 3e and 3f refer to literature and sources. How do you achieve these marks?
  5. What are the marks awarded for when plotting your graph?
  6. What must your conclusion be related to, to achieve the mark?
  7. For candidate 1, how many repeats of the experiment did they make?
  8. What did candidate 1 do correctly for the graph and what was incorrect?
  9. Mark Candidate 2’s evidence thoroughly yourself using the marking scheme and compare your answer to the commentary. Record your results and the comparison. Comment on both of these.
  10. CHOOSE a topic that would be suitable using the Physics Compendium https://mrsphysics.co.uk/n5/ Research some Underlying Physics and find a suitable graph that you can try to replicate.

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Properties of Matter Notes

March 2018- Snow Days but Miss Horn’s class should answer the following questions from the sheet  and the past paper questions below.

combined gas law questions word

combined gas law questions pdf

past paper questions

SG C 2013 – Q12

SG C 2011 – Q11, Q12a

SG C 2010 Q12

 

Here is the final set of notes that I am working on. These are my final copies which I hope haven’t many changes when they are proof read. If you’d like to proof read and get back to me with changes I’d be delighted. I really hope I’ve covered everything.

Properties of matter notes pdf

Properties of matter notes  word

Thanks to other Physics teachers who have provided resources for these notes.

 

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