ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
(NTC) thermistor - ansA component, the resistance of which decreases with increasing temperature
Acoustic impedance - ansThe product of the density and the speed of ultrasound in a substance
Activity - ansRate of decay
Alpha radiation - ansIonising radiation consisting of particles comprised of two protons and two neutrons
Alpha-particle scattering experiment is... - ansevidence of a small, charged nucleus
Amplitude - ansThe magnitude of the maximum displacement of the medium
Anion - ansNegatively charged ions
Annihilation - ansThe complete destruction of a particle and its anti particle in an interaction that releases
energy in the form of identical photons
Antinode - ansPoints of maximum amplitude on a stationary wave
Antiparticle - ansA particle with the same mass but opposite charge of another
Atomic mass unit - ansOne atomic unit is one-twelfth the mass of a neutral carbon-12 atom
Attenuation - ansThe decrease of intensity of electromagnetic radiation as it passes through matter and/or
space
Attenuation coefficient - ansA measure of the absorption of x-ray photons by a substance. Also called
absorption coefficient
Baryon - ansHadrons made with a combination of three quarks or three anti-quarks
Beta decay - ansA process where a proton turns into a neutron and releases a high energy electron and
an antineutrino, or where a neutron turns into a proton and releases a high energy positron and a neutrino
Beta radiation - ansIonising radiation consisting of fast moving electrons or positrons
Binding energy - ansThe energy required to dissemble the nucleus of a particular isotope into its
fundamental nucleons
Binding energy per nucleon - ansThe binding energy divided by the number of nucleons in the nucleus of
an isotope
Capacitance - ansThe charge stored per unit potential difference across a capacitor
Capacitor - ansA component that stores charge, consisting of two plates separated by an insulator
(dielectric)
Carbon-dating - ansA method for determining the age of organic material, by comparing the activities, or
the ratios, of carbon 14 to carbon 12 nuclei of dead material of interest and similar living material
CAT scan - ansComputer Axial Tomography; x-ray images taken in a ring around the body to produce a
composite 2d image
Cation - ansPositively charged ions
,ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Chain reaction - ansA self propagating reaction - the products from one event are able to initiate the next
Cloud chamber - ansA detector of ionising radiation consisting of a chamber filled with air, saturated with
vapour at a very low temperature so that droplets of liquid condense around ionised particles left along
the path of radiation
Coherent - ansTwo waves that have a constant phase difference
Collimator - ansPart of a gamma camera, a honeycomb of long thin tubes made from lead that absorbs
any photons arriving at an angle to the axis of the tubes so that a clear picture is obtained
Conductor - ansA material with a low resistance and a high number density
Conservation of charge - ansA conservation law that states that electric charge cannot be created nor
destroyed - total charge in any interaction must be the same before and after the interaction
Conservation of charge - ansCharge cannot be created or destroyed
Constructive interference - ansSuperposition of two waves that are in phase resulting in a larger
amplitude
Control rod - ansAbsorbs excess neutrons in fission reaction to prevent/slow chain reaction in reactor
core
Conventional current - ansDirection of flow of positive charge. It is the opposite direction to the flow of
electrons
Coolant - ansA fluid of a high specific heat capacity used to transfer heat from reaction chamber to the
boiler
Coulomb's Law - ansAny two point charges exert an electrostatic (electrical) force on each other that is
directly proportional to the product of their charges and inversely proportional to the square of their
separation
Coupling gel - ansA gel with acoustic impedance similar to that of skin smeared onto the transducer and
the patient's skin before an ultrasounds scan in order to fill air gaps and ensure that almost all the
ultrasound enters the patient's body
Critical angle - ansThe angle of incidence at a boundary that will produce an angle of refraction of 90°
Daughter nucleus - ansA new nucleus formed following a radioactive decay
De Broglie wavelength - ansThe wavelength of a particle, calculated using the de Broglie equation
Decay constant - ansThe probability of decay of an individual nucleus per unit time
Describe how ultrasound scanning is used to obtain diagnostic information about internal
structures of a body. - ans-Pulses of ultrasound (sent into the body)
-Wave / ultrasound / pulse / signal is reflected (at boundary of tissue)
-Time of delay used to determine depth / thickness
-The fraction of reflected signal is used to identify the
tissue
,ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Describe the differences between an A-scan and a
B-scan - ans-A-scan in one direction only / range or distance or depth
finding
-B-scan uses a number of sensors or a sensor in different
positions / angles (to build up a 2D/3D image)
Describe the piezoelectric effect - ansThe application of a p.d. across a material / crystal causes
an expansion / contraction / vibration
Destructive interference - ansSuperposition of two waves that are in antiphase resulting in a smaller
amplitude
Differences to Gravitational Fields - ansGravitational fields are only attractive, electrical fields can be
attractive and repulsive.
Diffraction - ansThe spreading of a wave when it encounters a gap or obstacle (e.g. water waves passing
through a harbour entrance)
Displacement - ansThe distance and direction of a point in the medium from its equilibrium position
Electric current - ansThe rate of flow of positive charge, usually measured in amperes
Electric field - ansA region where a charged particle will experience an electric force
Electric field strength - ansThe force experienced per unit positive charge at that point
Electric Potential - ansThe work done by an external force per unit positive charge to bring a charge from
infinity to a point in an electrical field
Electric Potential Difference - ansThe work done by an external force per unit positive charge to move a
charge between two points in an electrical field
Electrolyte - ansA liquid that contains ions that are free to move and so conducts electricity
Electromagnetic waves - ansTransverse waves with oscillating electric and magnetic field components
and that do not need a medium to propagate
Electromotive force (e.m.f) - ans"The electrical potential energy gained per unit charge passing through a
cell or battery. Equal to the work done per unit charge on the charge carriers."
Electronvolt (eV) - ansA derived unit of energy defined as the energy transferred when an electron passes
through a potential difference of 1 volt. 1 eV = 1.60 × 10-19J
Elementary charge, e - ansThe charge on one proton, equal to 1.60×10-19C
Exponential decay - ansA constant-ratio process in which a quantity decreases by the same factor in
equal time intervals (fixed time intervals)
Farad - ansUnit for capacitance equivalent to CV-1. 1F is 1C of charge stored per volt.
Faraday's law - ansThe EMF induced by a changing magnetic field is directly proportional to the rate of
change of magnetic flux linkage
, ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Flemming's left hand rule - ansA rule used determine the direction of the force acting on a current-
carrying wire in a magnetic field:
Free electron - ansAn electron in a metal that is not bound to an atom (delocalised) and is free to move
Frequency - ansThe number of complete waves passing a point per unit time or the number of oscillations
completed by a point in the medium per unit time.
Fundamental frequency - ansThe lowest frequency that an object can vibrate at
Fundamental particle - ansA particle that has no internal structure and hence cannot be divided into
smaller particles
Gamma radiation - ansIonising radiation consisting of high energy photons with wavelengths less than 10-
13m which travel at the speed of light
gamma ray - ans10^-12
Hadron - ansA particle made up of quarks and which can take part in strong force interactions
Half-life - ansThe time taken for half a sample of material to decay, or for the activity to decrease to half
its original value
Harmonic - ansAn integer multiple of the fundamental frequency
Impedance matching - ansThe use of two substances with similar acoustic impedance to minimise
reflection of sound waves at the boundary
In antiphase - ansParticles oscillating completely out of step with each other, phase difference π
In phase - ansParticles oscillating completely in step with each other, phase difference 0 or 2π
Induced fission - ansFission caused by the absorption of another particle
Infrared - ans10^-5
Insulator - ansA material that does not easily support an electric current due to having a high resistance
and a very low number density
Intensity - ansThe radiant power per unit area, proportional to amplitude squared
Intensity reflection coefficient - ansThe ratio of reflected intensity to incident intensity at a boundary
Interference - ansSuperposition of two progressive waves to produce a result wave that follows the
principle of superposition
Internal resistance - ansThe resistance of a power supply
Ion - ansAn atom that has either lost or gained electrons and so has a net charge
Ionising radiation - ansRadiation that can ionise atoms by removing some of their electrons, leaving
positive ions
Final.
(NTC) thermistor - ansA component, the resistance of which decreases with increasing temperature
Acoustic impedance - ansThe product of the density and the speed of ultrasound in a substance
Activity - ansRate of decay
Alpha radiation - ansIonising radiation consisting of particles comprised of two protons and two neutrons
Alpha-particle scattering experiment is... - ansevidence of a small, charged nucleus
Amplitude - ansThe magnitude of the maximum displacement of the medium
Anion - ansNegatively charged ions
Annihilation - ansThe complete destruction of a particle and its anti particle in an interaction that releases
energy in the form of identical photons
Antinode - ansPoints of maximum amplitude on a stationary wave
Antiparticle - ansA particle with the same mass but opposite charge of another
Atomic mass unit - ansOne atomic unit is one-twelfth the mass of a neutral carbon-12 atom
Attenuation - ansThe decrease of intensity of electromagnetic radiation as it passes through matter and/or
space
Attenuation coefficient - ansA measure of the absorption of x-ray photons by a substance. Also called
absorption coefficient
Baryon - ansHadrons made with a combination of three quarks or three anti-quarks
Beta decay - ansA process where a proton turns into a neutron and releases a high energy electron and
an antineutrino, or where a neutron turns into a proton and releases a high energy positron and a neutrino
Beta radiation - ansIonising radiation consisting of fast moving electrons or positrons
Binding energy - ansThe energy required to dissemble the nucleus of a particular isotope into its
fundamental nucleons
Binding energy per nucleon - ansThe binding energy divided by the number of nucleons in the nucleus of
an isotope
Capacitance - ansThe charge stored per unit potential difference across a capacitor
Capacitor - ansA component that stores charge, consisting of two plates separated by an insulator
(dielectric)
Carbon-dating - ansA method for determining the age of organic material, by comparing the activities, or
the ratios, of carbon 14 to carbon 12 nuclei of dead material of interest and similar living material
CAT scan - ansComputer Axial Tomography; x-ray images taken in a ring around the body to produce a
composite 2d image
Cation - ansPositively charged ions
,ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Chain reaction - ansA self propagating reaction - the products from one event are able to initiate the next
Cloud chamber - ansA detector of ionising radiation consisting of a chamber filled with air, saturated with
vapour at a very low temperature so that droplets of liquid condense around ionised particles left along
the path of radiation
Coherent - ansTwo waves that have a constant phase difference
Collimator - ansPart of a gamma camera, a honeycomb of long thin tubes made from lead that absorbs
any photons arriving at an angle to the axis of the tubes so that a clear picture is obtained
Conductor - ansA material with a low resistance and a high number density
Conservation of charge - ansA conservation law that states that electric charge cannot be created nor
destroyed - total charge in any interaction must be the same before and after the interaction
Conservation of charge - ansCharge cannot be created or destroyed
Constructive interference - ansSuperposition of two waves that are in phase resulting in a larger
amplitude
Control rod - ansAbsorbs excess neutrons in fission reaction to prevent/slow chain reaction in reactor
core
Conventional current - ansDirection of flow of positive charge. It is the opposite direction to the flow of
electrons
Coolant - ansA fluid of a high specific heat capacity used to transfer heat from reaction chamber to the
boiler
Coulomb's Law - ansAny two point charges exert an electrostatic (electrical) force on each other that is
directly proportional to the product of their charges and inversely proportional to the square of their
separation
Coupling gel - ansA gel with acoustic impedance similar to that of skin smeared onto the transducer and
the patient's skin before an ultrasounds scan in order to fill air gaps and ensure that almost all the
ultrasound enters the patient's body
Critical angle - ansThe angle of incidence at a boundary that will produce an angle of refraction of 90°
Daughter nucleus - ansA new nucleus formed following a radioactive decay
De Broglie wavelength - ansThe wavelength of a particle, calculated using the de Broglie equation
Decay constant - ansThe probability of decay of an individual nucleus per unit time
Describe how ultrasound scanning is used to obtain diagnostic information about internal
structures of a body. - ans-Pulses of ultrasound (sent into the body)
-Wave / ultrasound / pulse / signal is reflected (at boundary of tissue)
-Time of delay used to determine depth / thickness
-The fraction of reflected signal is used to identify the
tissue
,ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Describe the differences between an A-scan and a
B-scan - ans-A-scan in one direction only / range or distance or depth
finding
-B-scan uses a number of sensors or a sensor in different
positions / angles (to build up a 2D/3D image)
Describe the piezoelectric effect - ansThe application of a p.d. across a material / crystal causes
an expansion / contraction / vibration
Destructive interference - ansSuperposition of two waves that are in antiphase resulting in a smaller
amplitude
Differences to Gravitational Fields - ansGravitational fields are only attractive, electrical fields can be
attractive and repulsive.
Diffraction - ansThe spreading of a wave when it encounters a gap or obstacle (e.g. water waves passing
through a harbour entrance)
Displacement - ansThe distance and direction of a point in the medium from its equilibrium position
Electric current - ansThe rate of flow of positive charge, usually measured in amperes
Electric field - ansA region where a charged particle will experience an electric force
Electric field strength - ansThe force experienced per unit positive charge at that point
Electric Potential - ansThe work done by an external force per unit positive charge to bring a charge from
infinity to a point in an electrical field
Electric Potential Difference - ansThe work done by an external force per unit positive charge to move a
charge between two points in an electrical field
Electrolyte - ansA liquid that contains ions that are free to move and so conducts electricity
Electromagnetic waves - ansTransverse waves with oscillating electric and magnetic field components
and that do not need a medium to propagate
Electromotive force (e.m.f) - ans"The electrical potential energy gained per unit charge passing through a
cell or battery. Equal to the work done per unit charge on the charge carriers."
Electronvolt (eV) - ansA derived unit of energy defined as the energy transferred when an electron passes
through a potential difference of 1 volt. 1 eV = 1.60 × 10-19J
Elementary charge, e - ansThe charge on one proton, equal to 1.60×10-19C
Exponential decay - ansA constant-ratio process in which a quantity decreases by the same factor in
equal time intervals (fixed time intervals)
Farad - ansUnit for capacitance equivalent to CV-1. 1F is 1C of charge stored per volt.
Faraday's law - ansThe EMF induced by a changing magnetic field is directly proportional to the rate of
change of magnetic flux linkage
, ocr A Level Physics A H556/02 Mark Scheme June2023
Final.
Flemming's left hand rule - ansA rule used determine the direction of the force acting on a current-
carrying wire in a magnetic field:
Free electron - ansAn electron in a metal that is not bound to an atom (delocalised) and is free to move
Frequency - ansThe number of complete waves passing a point per unit time or the number of oscillations
completed by a point in the medium per unit time.
Fundamental frequency - ansThe lowest frequency that an object can vibrate at
Fundamental particle - ansA particle that has no internal structure and hence cannot be divided into
smaller particles
Gamma radiation - ansIonising radiation consisting of high energy photons with wavelengths less than 10-
13m which travel at the speed of light
gamma ray - ans10^-12
Hadron - ansA particle made up of quarks and which can take part in strong force interactions
Half-life - ansThe time taken for half a sample of material to decay, or for the activity to decrease to half
its original value
Harmonic - ansAn integer multiple of the fundamental frequency
Impedance matching - ansThe use of two substances with similar acoustic impedance to minimise
reflection of sound waves at the boundary
In antiphase - ansParticles oscillating completely out of step with each other, phase difference π
In phase - ansParticles oscillating completely in step with each other, phase difference 0 or 2π
Induced fission - ansFission caused by the absorption of another particle
Infrared - ans10^-5
Insulator - ansA material that does not easily support an electric current due to having a high resistance
and a very low number density
Intensity - ansThe radiant power per unit area, proportional to amplitude squared
Intensity reflection coefficient - ansThe ratio of reflected intensity to incident intensity at a boundary
Interference - ansSuperposition of two progressive waves to produce a result wave that follows the
principle of superposition
Internal resistance - ansThe resistance of a power supply
Ion - ansAn atom that has either lost or gained electrons and so has a net charge
Ionising radiation - ansRadiation that can ionise atoms by removing some of their electrons, leaving
positive ions
