P2 Extende Rsponse Flashcards
(24 cards)
A potential divider circuit (circuit 2) and a normal circuit (circuit 1)are used to measure the voltage and current across a filament lamp there is an EMF supply of 12 V to both circuits explain which circuit would be able to produce a graph where minimum current is 0.2 A and there is a range of values from 0 to 12 V , the maximum resistance in circuit one is 17.2 owns
The minimum current is 0.7 A which is not close to 0.2 A therefore circuit one cannot produce the range of values for current between 0 V and 12 V
However circuit two is a potential divider circuit therefore it is able to produce the data as the potential difference can be varied between 0 V and 12 V
Explain in terms of electromagnetic induction how a transformer may be used to step down voltage
When an alternating current flows through the primary coil and alternating magnetic field is introduced therefore there is a change in magnetic flux linkage of the secondary coil since EMF is proportional to the rate of change of magnetic flux linkage. An EMF is induced across the secondary coil if the number of turned on the secondary coil is less than the number of terms on the primary coil the EMF is less than the primary potential difference.
A charged positive ion travels perpendicular to a uniform magnetic field describe the path of this ion and a calculation that can be used to describe it
The iron will have a circular Paeth we can use Fleming‘s left-hand rule to find in which direction the force is acting and then we can use
Bqv = mv^2/ r
Define radius of the path to show its motion
Explain how the transducer both produces and receives ultrasound waves
A high frequency alternating. Potential difference is applied across a piezoelectric crystal causing it to stretch and compressed at a high frequency ultrasound waves are sent in pulses, between these posts a reflected ultrasound is incident on the Peezo Electric crystal causing the crystal to oscillate and an alternative potential difference is induced across the crystal
Describe an experiment that produces an electron defraction pattern
A cathode releases electrons through thermic emission through an evacuated tube. These electrons are then accelerated through a potential difference and these electrons are defected through a graphite with the atomic spacing of the Debralee wavelength of the electrons. The electrons are then detected on a screen where the defraction pattern appears.
Describe how vision of nuclei is induced and controlled in the nuclear reactor
Absorption of a neutron by a uranium nucleus, the uranium nucleus becomes unstable and the unstable nuclei undergoes fishing resulting in smaller nuclei daughter products and additional fast neutrons released
The moderator slows down the neutron so that they can be absorbed by the uranium nuclei and the process repeats from a chain reaction. The rate of the chain reaction is controlled by raising or lowering control rods which absorb access neutrons to allow one neutron per fission to cause further vision.
The energy released from the fusion of 1 kg of hydrogen is more than seven times the energy released by the vision of 1 kg kilogram of uranium compare the practicalities of using nuclear fusion of hydrogen with using nuclear vision of uranium to meet our energy needs
The technology for vision is already established however the technology for fusion is not yet established
Vision is a chain reaction self sustaining once initiated however fusion requires very high temperatures and pressures in order to initiate or continue a reaction
However, with vision there’s a finite amount of uranium and refusion there is a large abundance of hydrogen from the seawater
Vision produces highly radioactive waste which needs to be disposed of properly and fusion does not produce any radioactive waste
The probability of an accident accident for vision is greater than the probability of fusion as fusion is very unlikely to produce serious accident
Explain why high energy x-ray photons produce electrons and Poron as they passed through the body in radiotherapy
High energy x-ray futons interact with a nucleus and the energy of the x-rays is transformed into matter and antimatter which is the electron and positron
A stationary uranium nucleus decayed into a thorium nucleus and an alpha particle we are given the number of protons and neutrons in the uranium Ethereum nucleus and we are given the velocity of auditorium nucleus after the decay. How can we find the kinetic energy of the alpha particle?
Momentum is conserved therefore the momentum before equals the momentum after as the uranium nucleus is stationary. The momentum is equal to 0.
We can then form an equation 0= mv(th) + mv(a)
We can then use the data book to find the masses and the velocity of Dorum is given therefore we can find the velocity of the alpha particle then we just use the equation for kinetic energy
The uranium-238 (92 protons) nucleus starts the decay chain which ends with a nucleus of lead-206 (82 protons)
Show that 14 particles are emitted during this decay chain. Explain your reasoning.
Uranium can decay by both beta and alpha decay
The change in the atomic number is eight as 238= 206 + 4x +0y
Where x= alpha particles , y = beta particles and beta particles have no neutrons
The change in the atomic mass number is
92=82 + 2x +y we know that there has been eight omitted alpha particles therefore we can substitute this into the equation to find that there are six beta particles omitted therefore 6+18 = 14 particles
As the question says explain your reasoning you need to say that alpha particles are the only particles which changed the proton number and both beta and alpha particles can change the nuclear number
Describe how you would answer question 4a which is in your photos look it up it is a circuit diagram question of a box with four terminals
First you have to realise that the terminal CD has the lowest resistance and the greatest current therefore this is easily identify so you attach 100 a resistor in series and a voltage supply across the terminals CD then use V equals IR to find the current which is 0.06 A. Using this we can now identify other terminals of the box therefore switch out the hundred own resistor as 100 own resistor was only used to find the current in the terminal CD and attach the circuit to the other terminals and use the values to find the resistance and the current in each terminal therefore we can mark out which is AOD.
A loudspeaker is mountain on a bench and emits sound which is picked up by a microphone on the other end what is this an example of?
Simple harmonic motion
Describe how you can demonstrate in a laboratory that reflected light is plain polarised
Use a polarise filter and rotate the polar rising filter passing light through it and rotating it will change the intensity of the reflected light when the axes are aligned. It should’ve let maximum light through the other side when they are misaligned so perpendicular to each other they should let no light therefore the light has been plain polar
When does total internal reflection happen?
When the angle of incident is greater than the critical angle and the material is travelling from a material of lower refractive index to higher refractive index
There are 7.68x10^22 uranium nuclei ready to undergo nuclear fission, the energy released in each vision reaction is equivalent to the decrease in mass of 0.19u estimate the total energy produced from the fuel rod
Multiply the number of nuclei by 0.19u then multiply this by 931.5X10^6 to get the answer in electron volts then multiply by the elementary charge to give you an answer of 2.2X10^12
Explain how the reflection of ultrasound at a boundary between two tissues depend on the physical properties of the tissue 
Density of the tissue affects the wave speed therefore the impedance and if the two tissues have a different acoustic impedance then reflection will occur
The intensity of the reflected waves is given by “the equation of the equation book “
Explain the characteristics and describe the shape of an EMF against time graph for a magnet vertically falling through a coil
The EMF induced is directly proportional to the rate of change of magnetic flux linkage. There are two peaks that are opposite to each other as the EMF changes from a positive to a negative value as the rate of change of magnetic flux linking with the coil changes sign.
The EMF becomes zero at the middle of the coil as the rate of change of magnetic flux linkage is zero
The second peak of a negative amplitude is larger than the first peak amplitude. This is because the rate of change of magnetic flux linkage increases as the magnet lead to coil compared when it enters as it is accelerating out the coil
And the areas of the two curves for above and below have the same area as the total change of magnetic flux linkage entering the coil is the same as when it is leaving the coil
Explain how an ultrasound is used to measure the speed of blood flow in an artery
Pulses of the ultrasound are aimed at the probe. The detected frequencies of the reflected waves is different to the waves that are omitted and the ratio of these frequencies enables the speed of the blood to be calculated.
A magnet M is connected to a signal generator with a coil Y wrapped around it and attached to a wire attaching another magnet L with a coil X wrapped around it when the signal generator is switched on the magnet M oscillate in and out of the coil Y causing the magnetwrapped around L to also oscillate explain why
The movement of magnet M through the coil Y causes a change of flux linkage across the coilwrapped around Y therefore producing an EMF across it
This introduces a current through the coil X which introduces a magnetic field around the coil X which interact with the magnetic field of L which has been driven this causes an alternating force which makes L oscillate
Briefly describe an experiment to find the internal resistance of a cell and the EMF of a cell using a thermistor
Set up a circuit of a cell remember to draw the internal resistance on the circuit and connect an ammeter and series and a thermostat series then place a meter across the thermostat
Keep the thermostat in a water bath and use a Bunsen burner to change the temperature of the thermostat therefore varying the resistance of the thermostat and the resistance of the circuit. This intern varies de voltage of the circuit. 
At a point a proton has an equivalent motion in a circle at a constant speed, the electric feild that the proton is in and the proton has a downwards mag force how can we find the radius of the path of the proton
First find the resultant force from the electric and magnetic force, then use this in the equation
F=mv^2/r
Find the velocity by mag force= Bqv
Explain how an A-scan could be used to measure the thickness of a patience eye lense
Posters of ultrasounds are sent into the eye and reflections from the front and the back of the lens create processes displayed on a telescope. The thickness can be determined by the speed of the ultrasound and the time difference on the timebase setting.
Explain how the density of a nucleus depends on its nucleon number
Density is independent of the nucleus is nucleon number and the identity is constant for most radius is however nucleus is with larger nucleons tend to have larger R
A student set up a potential divider circuit search that a LDR and a resistor are placed in series with a DC supply with an ammeter in series, when light is incident on the Audi, the resistance of the Audi varies between 1500 ohms and 250 ohms, the student needs to choose between 1000 resistor a 750 own resistor and a 1500 own resistor to use as the fixed resistor in the circuit which of these resistors would give the largest scale change on the meter for the change in light  intensity , the voltage supply is 45V
In order for the largest scale change on the meter for the change in light intensity we need to test each of the resistors
For example, when the LDR has a maximum resistance of 1500 ohms and we use the fixed resistor with the resistance 1500 ohms the total resistance in the circuit would be 3000 ohms therefore I=45/3000=0.015, now when the LDR is at its minimum 250 ohms the total resistance in the circuit would be1750 ohms therefore I=45/1750 =0.026
Therefore, the change in current is 0.011
repeat this for all resistance and see which resistor produces the largest scale change in current
