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A2 Module 4 Waves, Fields and
Nuclear Energy |
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Introduction:
This is the first A2 module building on the key ideas and knowledge
covered in AS. The properties of waves are covered, gravitational and
electric fields are introduced, as are the magnetic effects of currents.
Candidates will also study the practical application of nuclear fission as
a source of energy. |
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Oscillations
and Waves |
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Questions on SHM from Breithaupt
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Characteristic features of simple harmonic motion Exchange of potential and kinetic energy in oscillatory motion Understanding and use of the following equations a = - (2pf)2x x = Acos2pft v = ±2pf ÖA2 - x2 Graphical rep representations linking displacement, velocity, acceleration time and energy Velocity as gradient of displacement /time graph Simple pendulum and mass -spring as examples and use of the equations T = 2pÖl/g simple pendulum T = 2pÖm/k spring pendulum Candidates
should have experience of the use of data logging techniques in analysing
mechanical and oscillatory systems |
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Free
and forced vibration old SHM multi-choice answers - commentary on the answers |
Qualitative treatment of free and forced vibration Resonance and the effects of damping Examples
of these effects from more than one branch of Physics e.g. production of
sound in a pipe instrument or mechanical vibrations in a moving vehicle
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Oscillation of the particles of the medium Amplitude, frequency, wavelength, speed, phase, path difference Recall and use of c
= fl |
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Longitudinal
waves and transverse waves
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Examples including sound and electro- magnetic waves Polarisation
as evidence for the nature of transverse waves; applications, e.g.
polaroid sunglasses |
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Super-
position
of waves, stationary waves
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The formation of stationary waves by two waves of the same frequency travelling in opposite directions; no mathematical treatment required Simple
graphical represent- ations of stationary waves, nodes and antinodes on
strings and in pipes.
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The concepts of path difference and coherence Require- ments of two source and single source double-slit systems for the production of fringes The appearance of the interference fringes produced by a double slit system. l
= ws / D |
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simple explanation of diffraction |
Appearance of the diffraction pattern from a single slit The plane transmission diffraction grating at normal incidence Optical details of the spectrometer will not be required Derivation of: nl= d sin q Applications, e.g. to spectral analysis of light from
stars |
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Recall
and use of C = Q /V |
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Energy
stored by capacitor
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Derivation and use of E = 1/2 QV and
interpret- ation of area under a graph of charge against p.d. |
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Graphical
rep- resentation
of charging and discharging of capacitors through resistors
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time constant = RC Calculation
of time constants including their determin- ation from graphical data |
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Quantitative
treatment of capacitor discharge |
Q = Qo e -t/RC Candidates
should have experience of the use of a voltage sensor and datalogger to
plot discharge curve for a capacitor |
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Uniform
motion in a circle |
w = v/r w = 2pf a = v2 / r = rw2 where
is w angular
speed |
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Centripetal
force equation |
Recall and use of F
= - mv2 / r |
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Gravity,
Newton’s law, the gravitational constant |
F = - Gm1m2 / r2 Methods
for measuring G are not included |
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Gravitational
field strength
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g=F/m g = -GM/r2 (radial field) g
= -DV/Dr |
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Gravitational
potential V |
V = -GM/r radial field) Graphical
represent- ations of variations of g and V with r |
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Motion
of masses in gravitational fields |
Circular
motion of planets and satellites including geo- synchronous orbits
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Coulomb’s
law, permittivity of free space |
Recall and use of F
= 1/4pe0 Q1Q2/r2
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Electric
field strength E |
Application, e.g. estimation of forces at closest approach in Rutherford alpha particle scattering E = F/Q E= V/d (uniform field) E
= 1/4pe0 Q/r2
(radial field) |
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Electric
potential |
V
= 1/4pe0 Q/r |
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Motion of charged particles in an electric field |
Trajectory
of particle beams |
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Similarities
and differences between electric and gravi- tational fields |
No
quantitative comparisons required |
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Force
on a current carrying wire in a magnetic field |
F
=
BIl (field
perpendicular to current) |
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Motion
of charged particles in a magnetic field |
F = BQv (field perpendicular to velocity) Circular
path of particles; application, e.g. charged particles in a cyclotron |
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Magnetic
flux density B, flux f flux linkage |
f
= BA, B normal to A |
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Electro-
magnetic
induction
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Simple experimental phenomena, Faraday’s and Lenz’s laws For a flux change at a uniform rate magnitude of induced e.m.f. = N Df / Dt Applications,
e.g. p.d. between wing-tips of aircraft in flight |
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Mass
and energy
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Simple calculations on nuclear trans- formations; mass difference; binding energy Atomic mass unit, u Conversion
of units; 1u = 9 E = mc² Appreciation that E = mc² applies to all energy changes Graph of average binding energy per nucleon against nucleon number, A Fission and fusion processes. |
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Induced
fission |
Induced fission by thermal neutrons Possibility of a chain reaction Critical mass Need for a moderator in thermal reactors Control of the reaction rate Factors influencing choice of material for moderator, control rods and coolant Examples
of materials |
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Safety
aspects |
Fuel used, shielding, emergency shut-down Production,
handling and disposal of active wastes |
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Artificial
trans- mutation |
Production
of man-made nuclides and examples of their practical applications, e.g. in
medical diagnosis. |
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Waves and nuclear applications past questions from old A-level PH02 Summer2001 to Spring1998 |
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Waves and nuclear applications past questions from old A-level PH02 Summer1997 to Spring1995 |
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Further Links |