When a metal plate is heated, electrons bubble to the surface and escape
1 of 24
How does an Electron Gun work
Uses a resistor to heat a plate to produce thermionic emission, and a positive plate used to attract the electrons away from the ions they created
2 of 24
Describe how to find the Potential Difference that an electron experiences using its velocity
find the kinetic energy ((1/2)mv^2) in eV, by definition this is the voltage the electron experiences
3 of 24
Describe how protons are isolated for use in particle colliders
Hydrogen gas is passed through a large P.D, electrons attracted to negative plate and protons have been isolated
4 of 24
Explain how particle accelerators can be used to produce X-rays
Electrons are accelerated, then fired at a metal block, energy is gained, electrons move up energy levels, large drop down means high frequency (X-rays)
5 of 24
How does a cloud chamber detect particles?
Charged particles will ionise the air, air is supersaturated from low temp, ionisation allow water drops to form which form a visible track
6 of 24
What distinguishes a Cloud chamber from a Bubble Chamber?
High energy electrons are deflected from the outside but occasionally pass through, indicating localized areas of mass and charge
8 of 24
What is the name and symbol for an antielectron?
Positron: e+
9 of 24
Why might kinematic equations suggest a particle is travelling faster than light?
They don't account for the increase in mass described the special relativity equation E=m(c^2) hence velocity appears higher
10 of 24
Why are particles and antiparticles always produced together from energy
Antiparticles have the opposite charge to the regular particle, so charge is conserved (before (energy) =0, after =0)
11 of 24
How are positrons used in PET scans?
Oxygen-15 injected into blood, decays via positron emission, positron annihilates, photons emitted, emitted photons detected. brain activity shown (more active parts use more oxygen)
12 of 24
Define 'Baryons'
Particles consisting of 3 quarks or 3 antiquarks
13 of 24
Define 'Mesons'
Particles consisting of two quarks, a quark and an antiquark
14 of 24
Observations of rutherfords' experiment
Majority of alphas went straight through, some of alphas deflected by 180 degrees, alphas repelled
15 of 24
Define 'Hadrons'
Particles that experience the strong interaction (protons and neutrons)
16 of 24
What is the Baryon Number?
The number of baryons involved in a reaction
17 of 24
Define 'Leptons'
Particles that don't experience the strong interaction
18 of 24
What do all baryons eventually decay to?
A proton, the only stable baryon
19 of 24
Why are electron-positron pairs the most common to be produced from energy?
They have relatively low mass hence less energy required
20 of 24
What is the energy source of most particle antiparticle pair productions?
Gamma ray photons
21 of 24
What is released when a particle-antiparticle pair annihilate?
A pair of gamma rays
22 of 24
What happens if quark separation is attempted
The energy used to separate quarks to overcome the strong force produces a quark-antiquark pair (meson)
23 of 24
What four properties are always conserved in particle reactions?
Charge, Baryon Number, Energy, and Momentum
24 of 24
Other cards in this set
Card 2
Front
How does an Electron Gun work
Back
Uses a resistor to heat a plate to produce thermionic emission, and a positive plate used to attract the electrons away from the ions they created
Card 3
Front
Describe how to find the Potential Difference that an electron experiences using its velocity
Back
Card 4
Front
Describe how protons are isolated for use in particle colliders
Back
Card 5
Front
Explain how particle accelerators can be used to produce X-rays
Comments
No comments have yet been made