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OCR A LEVEL PYSICS EXAM WITH ACTUAL
CORRECT ANSWERS
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What type of wave doesn't tranfer energy? - CorreCt Answers -Stationary
waves

What is the fundamental frequency of a string? - CorreCt Answers -The
lowest frequency which produces a stationary wave on the string
...


What determines the pitch produced by a stationary wave in a musical
instrument? - CorreCt Answers -The frequency of the 1st harmonic

What determines the loudness of sound? - CorreCt Answers -The amplitude
of the sound wave

Why can only certain frequency stationary waves be produced on a
stretched string? - CorreCt Answers -There must be nodes at the fixed ends
and only certain frequencies/wavelengths allow this
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6x10^-19

How do convert from J to eV? - CorreCt Answers -divide by 1
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d
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How can the threshold p
...
of an LED be used to find photon energy? CorreCt Answers -The energy transferred by the electrons (e x V) is equal to
the energy of the photons produced (hf)
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What is the atomic structure of a metal? - CorreCt Answers -A lattice of
positive ions surrounded by a sea of free electrons
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What is the effect on an electron of absorbing a photon? - CorreCt Answers
-The electron gains the energy of the photon

What effect does increasing the frequency of a monochromatic light source
have on photoelectrons produced? - CorreCt Answers -Photoelectrons will
have a greater maximum kinetic energy

What is the effect of increasing the intensity of a monochromatic light
source on photoelectrons produced? - CorreCt Answers -More
photoelectrons will be produced but they will have the same maximum
kinetic energy

Why does the kinetic energy of photoelectrons from monochromatic light
vary in the photoelectric effect? - CorreCt Answers -The work function is a
minimum energy
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What two factors that determine the maximum kinetic energy of
photoelectrons? - CorreCt Answers -The frequency of the light and the work
function of the metal

What determines the rate at which energy is delivered by a wave? - CorreCt
Answers -Intensity/amplitude of the wave

What is hf in Einstein's photoelectric effect equation (hf = 𝜙 + KE(max)) CorreCt Answers -The energy of the incident photon
...


What is KE(max) in Einstein's photoelectric effect equation (hf = 𝜙 +
KE(max)) - CorreCt Answers -The maximum kinetic energy of the
photoelectrons

According to the wave model how is energy transferred from light to
electrons in a metal? - CorreCt Answers -It is delivered continuously and
builds up over time

If light is above the threshold frequency, how long will it take for
photoelectrons to start being produced? - CorreCt Answers -Photoelectrons
can be produced instantaneously when the light hits the metal

What happens if very intense light that is below the threshold frequency is
used? - CorreCt Answers -No photoelectrons are produced, regardless of
intensity
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What is the key piece of evidence for wave particle duality? - CorreCt
Answers -When an electron beam passes through polycrystaline graphite it
produces a diffraction and interference pattern pattern
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What is the value of the prefix T (tera) - CorreCt Answers -10¹²

What is the value of the prefix G (giga) - CorreCt Answers -10⁹

What is the value of the prefix M (mega) - CorreCt Answers -10⁶

What is the value of the prefix k (kilo) - CorreCt Answers -10³

What is the value of the prefix d (deci) - CorreCt Answers -10⁻¹

What is the value of the prefix c (centi) - CorreCt Answers -10⁻²

What is the value of the prefix m (milli) - CorreCt Answers -10⁻³

What is the value of the prefix μ (micro) - CorreCt Answers -10⁻⁶

What is the value of the prefix n (nano) - CorreCt Answers -10⁻⁹

What is the value of the prefix p (pico) - CorreCt Answers -10⁻¹²

What is the accuracy of measurements? - CorreCt Answers -How close a
measurements are to the true value
...


What is measurement error? - CorreCt Answers -The difference between
the measured value and the true value of the quantity
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What is the main method for correcting for random errors? - CorreCt
Answers -Taking repeated measurements and finding the mean
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What is a zero error? - CorreCt Answers -A systematic error that arises from
an instrument reading reading a non-zero reading when nothing is being
measured
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What is a percentage uncertainty? - CorreCt Answers -The absolute
uncertainty stated as a percentage of the measured value
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How do you combine uncertainties when measurements are multiplied or
divided? - CorreCt Answers -Add together the percentage uncertainties
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What is a scalar quantity? - CorreCt Answers -A quantity with magnitude
but no direction
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When adding two perpendicular vectors what can you use to find the
direction of the resultant? - CorreCt Answers -Pythagoras' Theorem

When adding two perpendicular vectors what can you use to find the
magnitude of the resultant? - CorreCt Answers -Trigonometry

What is vector resolution? - CorreCt Answers -The process of splitting a
vector into two perpendicular components
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How is the resultant found in a vector diagram when adding several vectors
together? - CorreCt Answers -Join the vectors nose to tail and the resultant
is from the tail of the first to the nose of the last vector
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What is the effect of mass on the acceleration for an object in free-fall? CorreCt Answers -None

What is the relationship between displacement and time for an object
falling freely from rest? - CorreCt Answers -Displacement is proportional to
time squared (sαt²)

What is a projectile - CorreCt Answers -An object acted upon only by the
force of gravity

What shape is the path of a projectile? - CorreCt Answers -Parabolic

What is the initial vertical velocity of an object projected horizontally? CorreCt Answers -Zero

What angle of projection that results in maximum range - CorreCt Answers
-45°

Ignoring air resistance what is the acceleration of a projectile? - CorreCt
Answers -Always g downwards

How does horizontal velocity vary in projectile motion? - CorreCt Answers It is constant

If a projectile returns to its starting height - CorreCt Answers -Initial and
final velocities have the same magnitude

What equation used for the horizontal component of projectile motion? CorreCt Answers -Displacement = Velocity x time (since horizontal velocity
is constant)

What aspect links the vertical and horizontal motion of a projectile CorreCt Answers -Time taken to fall

Why can SUVAT equations can be used for the vertical component of
projectile motion - CorreCt Answers -Since the motion is in a single
direction with a constant acceleration

What is the vertical velocity at the peak of projectile motion? - CorreCt
Answers -Zero

What is the centre of mass of an object? - CorreCt Answers -The point at
which the weight can be assumed to act
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What is weight? - CorreCt Answers -The force due to gravity that acts
through an objects centre of mass
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What is drag? - CorreCt Answers -The resistive force that acts on an object
moving through a fluid

What is tension? - CorreCt Answers -The force within a stretched object
such as a cable or rope
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What is a normal contact force? - CorreCt Answers -A force that acts
perpendicular to a surface when an object rests on it
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How do you calculate the component of weight acting perpendicular to a
slope? - CorreCt Answers -W cos (θ) where θ is the angle between the slope
and horizontal
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What is a moment? - CorreCt Answers -The turning effect produced by a
force
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What is the principle of moments? - CorreCt Answers -For an object in
rotational equilibrium the sum of the clockwise moments about any point is
equal to the sum of anticlockwise moments about that point
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How do you calculate the moment of a couple? - CorreCt Answers -Force x
perpendicular distance between the lines of action of the forces
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What is a resultant/net force? - CorreCt Answers -The vector sum of forces
acting on an object

What is the density of a substance? - CorreCt Answers -mass per unit
volume
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What is energy? - CorreCt Answers -The capacity of one object or system to
do work (or cause a change) on another
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What is the principle of conservation of energy? - CorreCt Answers -The
energy of a closed system always remains constant
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What form of energy is due to the motion of a mass? - CorreCt Answers kinetic energy

What form of energy is due to the position of a mass in a gravitational field?
- CorreCt Answers -gravitational potential energy

What form of energy is due to the bonds between atoms in a substance? CorreCt Answers -chemical energy

What form of energy is due to the a reversible change in shape of an object?
- CorreCt Answers -elastic potential energy

What form of energy is due to the position of a charge in an electric field? CorreCt Answers -electrical potential energy

What form of energy is due to the forces between protons and neutrons in
an atom? - CorreCt Answers -Nuclear energy

What form of energy is due to electromagnetic waves? - CorreCt Answers Radiant energy

What form of energy is due to the mechanical wave motion of atoms? CorreCt Answers -Sound energy

What form of energy is due to randomly distributed potential and kinetic
energies of the atoms within a system? - CorreCt Answers -Thermal energy

What effect does friction have on the energy of a moving object? - CorreCt
Answers -Transfers kinetic energy primarily to thermal energy

Describe the energy transformations for an object sliding downhill at
constant speed
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Describe the energy transformations for a vehicle travelling uphill at
constant speed
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How is % efficiency calculated? - CorreCt Answers -(Useful output
energy/total input energy) x 100

What is a tensile force? - CorreCt Answers -A force produces an extension
of the object
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What is Hooke's Law? - CorreCt Answers -Force is proportional to
extension so long as the elastic limit is not exceeded
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What is plastic deformation? - CorreCt Answers -A permanent change in
shape that remains once the load is removed
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What are the units of force constant (k) - CorreCt Answers -Nm⁻¹

What is represented by the area under a force-extension graph? - CorreCt
Answers -The work done stretching the object
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What is tensile stress? - CorreCt Answers -The force applied per unit cross
sectional area
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What is a ductile material? - CorreCt Answers -A material which ccan be
drawn into a wire of hammered into thin sheets
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What is the yield point of a material? - CorreCt Answers -The point at
which the material starts to extend rapidly as stress increases
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What is the breaking strength of a material? - CorreCt Answers -The stress
at the point of fracture
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What are the units of Young Modulus? - CorreCt Answers -Pa OR Nm⁻²

When does the Young Modulus apply to a material? - CorreCt Answers When stress is proportional to strain OR when it is obeying Hooke's law

How do you find the Young Modulus from a stress-strain graph? - CorreCt
Answers -The gradient of the initial straight line region
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What is a brittle material? - CorreCt Answers -A material the show only
elastic behaviour up to its breaking point, without plastically deforming
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What is Newton's 1st Law of motion? - CorreCt Answers -An object will
remain at rest of move at a constant velocity unless acted upon by a
resultant force

What is Newton's 3rd Law of motion? - CorreCt Answers -When two objects
interact they exert forces on each other that are equal in magnitude,
opposite in direction and of the same type of force
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What two sets of units can be used for momentum? - CorreCt Answers -Ns
OR kgms⁻¹

How is the momentum of an object calculated? - CorreCt Answers -Mass ×
velocity (p=mv)

What is the principle of conservation of momentum? - CorreCt Answers The total momentum in a system of interacting objects is constant provided
no external force acts
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Area under a force time graph - CorreCt Answers -Impulse

Gradient of a momentum-time graph - CorreCt Answers -Resultant force

What is the change in momentum when an object of momentum p collides
elastically at right angles with a wall? - CorreCt Answers --2p

When can F=ma be used? - CorreCt Answers -When an object has constant
mass
...


What is the Coulomb in base units? - CorreCt Answers -AS

What is a charge carrier? - CorreCt Answers -A charged particle capable of
transferring electric current
...


What is a metallic conductor? - CorreCt Answers -A material comprising a
lattice of positive ions and delocalised electrons that carry electrical current

Which direction does conventional current flow? - CorreCt Answers -From
positive to negative
...


What is an ion? - CorreCt Answers -A non-neutral atom or molecule
...


What is an anion? - CorreCt Answers -A positively charged ion
...


What is a cathode? - CorreCt Answers -A negative electrode
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State Kirchoff's first law
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What is n in the equation I = nAve and what are its units? - CorreCt
Answers -Number density of free charge carriers m⁻³

What is A in the equation I = nAve? - CorreCt Answers -Cross-sectional
area of the conductor
...
6x10⁻¹⁹C)

What is v in the equation I = nAve? - CorreCt Answers -The drift velocity of
the charge carriers
...


What is a semiconductor? - CorreCt Answers -A material with an
intermediate number density of charge carriers ~10¹⁷m⁻³

What is potential difference? - CorreCt Answers -The work done per unit
charge between two points

What is the SI unit for potential difference? - CorreCt Answers -Volt (V)

What units are equivalent to the volt? - CorreCt Answers -Joules per
Coulomb (JC⁻¹ )

What is EMF (Electromotive force)? - CorreCt Answers -The work done per
unit charge supplied to the charge carriers

How is a voltmeter connected? - CorreCt Answers -In parallel
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What is thermionic emission? - CorreCt Answers -The emission of electrons
from the surface of a heated metal
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d
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What is Ohm's Law? - CorreCt Answers -For a metallic conductor at
constant temperature the p
...
is proportional to current
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How is resistance calculated? - CorreCt Answers -V/I

What units are equivalent to an Ohm? - CorreCt Answers -VA⁻¹

Why does resistance increases with temperature? - CorreCt Answers -The
amplitude of lattice ion vibrations increases causing more frequent
collisions between electrons and lattice ions, leading to the electrons
doingm more work as they move through the wire
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What is an Ohmic conductor? - CorreCt Answers -An object for which p
...

is proportional to current
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What are the units of resistivity? - CorreCt Answers -Ωm

What is ρ in R = ρL / A? - CorreCt Answers -The resitivity of the material
...


What is A in R = ρL / A? - CorreCt Answers -The cross-sectional area of the
wire

As a metal gets hotter what happens to its resitivity? - CorreCt Answers -It
increases
...


Why does resistance of a thermistor fall as temperature increases? CorreCt Answers -The number density of charge carriers increases
...


Why does the resistance of an LDR as light intensity changes? - CorreCt
Answers -Light increases the number density of charge carriers in the LDR
...


What happens to the resistance of an LDR as light intensity increases? CorreCt Answers -It decreases
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How many Joules are equavlent to a kWh - CorreCt Answers -3
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- CorreCt Answers -Sum of the EMFs is equal to
the sum of the potential drops around a closed circuit loop
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What can we say about the pd across parallel branches in a circuit? CorreCt Answers -It is the same for each branch

How do find the total pd across several components in series? - CorreCt
Answers -It is equal to the sum of the pds across each component

How do you find the total EMF from cells connected in series with the same
polarity? - CorreCt Answers -Their EMFs are added

How do you find the total EMF from cells connected in series with opposite
polarity? - CorreCt Answers -The total EMF is the difference between their
EMFs

How do you calculate the total resistance of resistors in series? - CorreCt
Answers -Sum of the individual resistances

What is the total resistance of n identical resistors in series? - CorreCt
Answers -n x R

What is the total resistance of n identical resistors in parallel? - CorreCt
Answers -R ÷ n

How do you calculate the resistance of resistors in parallel? - CorreCt
Answers -1/RT=1/R1+1/R2
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What happens to the terminal pd of a source as the current supplied
increases? - CorreCt Answers -It falls due to the increasing lost volts to the
internal resistance
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What is the relationship between EMF, terminal pd and lost volts? CorreCt Answers -EMF = terminal pd + lost volts

How do you find the internal resistance from a graph or terminal pd against
current? - CorreCt Answers --gradient

How do you find the EMF from a graph or terminal pd against current? CorreCt Answers -y-intercept

What is a potential divider? - CorreCt Answers -Two or resitances in series
with a fixed source of EMF
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How can a light sensor be made? - CorreCt Answers -By creating a potential
divider containing an LDR
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What component can be used to supply an adjustable output pd? - CorreCt
Answers -A potentiometer
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What is a transverse wave? - CorreCt Answers -A wave in which the
oscillations are perpendicular to the direction of wave propagation

What is a longitudinal wave? - CorreCt Answers -A wave in which the
oscillations are parallel to the direction of wave propagation

Give an example of a longitudinal wave - CorreCt Answers -Sound, primary
seismic waves

Give an example of a transverse waves - CorreCt Answers -Waves on a
stretched string, secondary seismic waves, electromagnetic radiation

What are the regions of high pressure in a longitudinal wave called? CorreCt Answers -Compressions

What are the regions of low pressure in a longitudinal wave called? CorreCt Answers -Rarefactions

What is the displacement of a wave? - CorreCt Answers -The distance of a
particle in the medium from it's equilibrium position in a particular
direction
...


What is the amplitude of a wave? - CorreCt Answers -Maximum
displacement of the medium from the equilibrium position
...


What is the relationship between frequency and time period? - CorreCt
Answers -f = 1/T or inverse proportionality

How many radians of phase are there in one complete wave cycle? CorreCt Answers -2π rad

What term describes a phase difference of zero between two points on a
wave? - CorreCt Answers -In phase

What term describes a phase difference of pi radians between two points on
a wave? - CorreCt Answers -In antiphase

What is the phase difference between points half a wavelngth apart? CorreCt Answers -180 degrees OR π rad

What is the phase difference between points quarter of a wavelngth apart? CorreCt Answers -90 degrees OR π/2 rad

What is an oscillation? - CorreCt Answers -A displacement one way and
then the other about an equilibrium position
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What effect does reducing the size of a single slit have on diffraction? CorreCt Answers -Diffracted waves spread out more

What is the effect of decreasing the wavelength on diffraction? - CorreCt
Answers -Diffracted waves spread out less

What is meant by the intensity of a wave? - CorreCt Answers -Intensity is
the energy delivered by the wave per second per square metre normal to the
wave

How is the intensity of a wave related to the amplitude? - CorreCt Answers Intensity is proportional to amplitude squared
...


What is the difference between mechanical waves and electromagentic
waves? - CorreCt Answers -EM waves don't require a medium
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What is the speed of all EM waves in a vacuum/air? - CorreCt Answers 3x10⁸ms⁻¹

List the regions of the EM spectrum in order of incresasing wavelength
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State the range of wavelengths (in powers of 10) of radio waves - CorreCt
Answers ->10⁻¹

State the range of wavelengths (in powers of 10) of microwaves - CorreCt
Answers -10⁻¹ - 10⁻³

State the range of wavelengths (in powers of 10) of infrared - CorreCt
Answers -10⁻³ - 10⁻⁶

State the range of wavelengths of visible light - CorreCt Answers -7x10⁻⁷ 4x10⁻⁷

State the range of wavelengths (in powers of 10) of ultraviolet - CorreCt
Answers -10⁻⁷ - 10⁻⁸

State the range of wavelengths (in powers of 10) of X-rays - CorreCt
Answers -10⁻⁸ - 10⁻¹³

State the range of wavelengths (in powers of 10) of gamma rays - CorreCt
Answers -<10⁻¹⁰

Why can't longitudinal waves be polarised? - CorreCt Answers Longitudinal waves already only have a single driection of oscillation
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- CorreCt Answers -LCD screens, 3D TV,
polarimetry in manufacturing, anti-glare sunglasses

What effect does reflection have on the polarisation of light? - CorreCt
Answers -Reflected light is partially polarised in the plane of the surface
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The angle of incidence must be greater than the critical angle
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What is the principle of superposition - CorreCt Answers -When two waves
meet at a point the resultant displacement is the (vector) sum of the
displacements of the individual waves
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What is constructive interference? - CorreCt Answers -When two waves
superpose in antiphase causing a decreased amplitude
...


What is an interference pattern? - CorreCt Answers -A pattern of regions of
constructive and destructive interference produced by coherent sources of
waves
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What name is given to light of a single frequency/wavelength? - CorreCt
Answers -Monochromatic

Why did Young place a single slit before the double slit? - CorreCt Answers
-To ensure the light from each of the double slits was in phase
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How does amplitude vary in a stationary wave? - CorreCt Answers -It varies
continuously along the wave
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