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34 Cards in this Set
- Front
- Back
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In an inelastic collision, kinetic energy is...? (1) |
Not conserved |
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A baryon contains...? (1) |
Three quarks or anti-quarks |
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A meson contains...? (1) |
One quark and one anti-quark |
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What is the point charge for a positively charged particle? (3) |
8 arrows starting from circle, evenly spaced, pointing AWAY from centre |
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Explain the role of an electric field in a particle detector (3) |
Can be used to accelerate particles, Direction of force indicates charge, a=EQ/m |
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Explain the role of a magnetic field in a particle accelerator (3) |
Produces circular motion, Direction of force indicates polarity, Momentum found from radius, r=p/BQ |
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In an induction motor, an alternating current is supplied to a stationary coil. Explain how a current is induced in the rotating coil (4) |
The stationary coil becomes an electromagnet, This field is changing (AC input), This magnetic field passes through the rotating coil, This leads to an induced emf |
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Describe how a metal disc can be made to emit electrons (2) |
Disc is heated, Thermionic emission, |
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Describe how you could measure the angle x at which a beam in an electric field is deflected (3) |
Measure horizontal displacement from plates to screen, Measure vertical displacement from centre of screen, tan x |
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Explain why the discovery of one quark would enable physicists to confidently predict the existence of another (1) |
Quarks come in pairs, Symmetry |
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How do the properties of a proton and anti-proton compare? (2) |
Same mass, Opposite charge |
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Why is GeV/c a valid unit for momentum (2) |
GeV is a unit of energy, E = mc^2 E/c = mc = momentum |
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Suggest why it takes a long time to find experimental evidence for a quark (2) |
Large amounts of energy required, Availability of antimatter is poor as it is difficult to store |
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The area under a force-time graph represents...? (1) |
Change in momentum |
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Flux linkage is measured in...? (1) |
Weber |
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For a coil of wire attached to a split ring commutator, and an electric motor, placed inside a magnetic field, explain why the coil turns and continues to rotate (4) |
Coil experiences a vertical force on the sides adjacent to magnet, Opposite vertical forces on either side of coil, Indication of anti/clockwise motion, Commutator switches current direction |
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When a coil in a magnetic field is connected to a d.c motor, why does its current begin large and then decreases as the coil turns faster (4) |
Flux is cut, This induces an emf, E.m.f increases with speed, E.m.f opposes current, |
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What is meant by a fundamental particle? (1) |
Cannot be split further |
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Outline the atomic processes that produce emission spectra (3) |
Electron increases in energy level when absorbing a specific frequency, Electron drops down to original state, Energy produced is dependant on gap |
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Describe Rutherfords key observations of the alpha particle scattering experiment (3) |
Most alpha went straight through, Some were deflected, Very few came straight back |
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State the main features of a linac (3) |
Consists of long horizontal tubes, They have alternating potential difference, The length of the tubes increase |
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Why are electrons useful for investigating nuclear structure? (1) |
Wavelength is smaller than nuclei |
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Suggest why electrons are scattered at large angles when fired at protons (2) |
The proton is not uniform, The proton contains quarks |
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Explain the purpose of a magnetic field in a cyclotron (2) |
Force on particles is at right angles to motion, Causes circular motion |
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Explain why the potential difference across the two dees in a cyclotron is alternating (2) |
The protons are accelerated in the gaps between dees, Every half rotation the polarity of dees change |
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In a newton's cradle experiment, explain how a student could investigate whether momentum is conserved during this event (4) |
Momentum conserved means momentum before = momentum after, Measure the initial velocity of first ball, Calculate the velocity of second ball after impact, If velocities are the same then momentum is conserved as my=mv as mass is the same |
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When charging a capacitor, the variation of charge against voltage graph is...? (1) |
Straight positive line |
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The de Broglie equation is used to calculate...? (1) |
The wavelength of a moving electron |
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What does the minus sign in € equation indicate? (3) |
Lenz's law, The induced emf direction opposes the change that produced it |
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Explain the propulsion method (4) |
Momentum conservation, Total momentum = 0, Momentum of forward body = momentum of backwards body, Resulting bodies move in opposite directions |
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How does a capacitor across the terminals of a power supply produces a constant voltage? (2) |
The capacitor charges up, If voltage is constant the capacitor will not discharge |
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How would you demonstrate how the initial momentum of a particle relates to its 2 resulting particles momenta (2) |
Draw a triangle, Use pythagoras |
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Explain the process by which a proton is given energy in a particle accelerator (3) |
Electric field does work on proton, E = qV |
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How do you convert MeV/c to kg? (2) |
Times by charge on an electron, Divide by c squared |
