Particles Flashcards
What is an electric field?
An electric field is a region in which an electric charge experiences a force.
What is a magnetic field?
A magnetic field is a region in which a moving electric charge experiences a force.
What rules must be followed when drawing electric field lines?
- Must touch the surface at 90 degrees
- Away from Positive Charge
- Parallel lines if parallel plates, spaced equally apart
- Field lines are closer together when the field strength is greater
- Electric Field lines DO NOT CROSS OVER EACH OTHER.
Why do moving charges experience a force in a magnetic field?
moving charges have a magnetic field.
What will happen if a charged particle enters a magnetic field perpendicular to the field?
The charge will experience a force at right angles to it’s motion and it will be steered into a circular path.
What will happen if a charged particle enters a magnetic field parallel to the field?
It will just stay the same/ nothing will happen
What shape placed in a grid represents a magnetic field going into the page?
A grid of crosses
What shaped placed in a grid represents a magnetic field coming out of the page?
A grid of dots
Explain the right hand rule
Acronym FBI
F - Force on the charge (thumb)
B - magnetic field (pointer finger)
I - Direction of moving charge ( second finger)
Shoot a gun with these three finger and then move the second finger to ninety degrees with the pointer finger.
ONLY APPLIES TO ELECTRONS
What is a Particle Accelerator?
A particle accelerator moves charged particles from rest to very high velocities
How does a Linear Accelerator accelerate particles?
Accelerates particles using alternating electric fields in a straight line towards a target at the end of a long tunnel.
- Requires AC Supply
How does a cyclotron accelerate particles?
Uses electric fields to accelerate the particles between the two ‘dees’ and magnetic fields to steer the particles into a circular path
- AC Current
How does a synchotron accelerate particles?
Synchronises multiple beams of particles using electric and magnetic fields
What are the three conclusions to rutherford’s gold foil experiment
- Most of the atom is empty space
- The atom has a tiny nucleus at it’s centre that contains most of the mass of the atom
- The nucleus is positively charged.
What is a fundamental particle?
A Fundamental Particle is a particle that cannot be split/ be broken down any further
Define Voltage
Voltage is defined as the Energy (Work Done) required to move 1 coulomb of charge in an electric field.
What is anti-matter
For every matter particle there is an equivalent anti-matter particle that has the same mass but the opposite electric charge.
What quarks make up a baryon
Any 3 quarks
What quarks make up a meson
An anti-quark and a quark
What is the evidence for quarks?
Particle Accelerators
What is evidence for the neutrino
Beta decay
Explain the symbol of an element
Top Number is the Mass Number- This is the number of neutrons add the number of protons.
The Bottom number is the Atomic Number - This is the number of protons in a nucleus.
What is the charge on an Alpha particle?
+2 - The alpha particle is a helium nucleus ( 2 protons + 2 neutrons)
Describe beta decay
Beta decay is a fast moving electron so has a charge of -1
It occurs when a neutron changes to a proton. - KEY FOR NUCLEAR REACTION DIAGRAMS
Describe gamma radiation
Gamma is a e.m wave so has no charge and no mass.
What is nuclear fusion?
Nuclear fusion is when 2 small nuclei are fused together to form a larger nucleus.
This only happens under extreme pressure an temperature conditions
What is a risk associated with fusion reactors?
Containing plasma at extremely high temperatures with magnetic fields is difficult ( we are essentially trying to make a star on earth)
What is nuclear fission?
The process in which an unstable, heavy atomic nucleus splits into two or more lighter nuclei (called fission fragments), with energy being released
What is the irradiance of a light source?
The Irradiance of a light source is the total energy per second (power) falling on a surface of an area of one square metre (m^2)
What is the Irradiance calculation?
I= P/A
I - Irradiance
P - Power
A- Area
What is the Inverse square law?
If the distance doubles, the surface area gets 4 times bigger, so the irradiance decreases by 4 times.
How do you verify Id^2 = Id^2
I=K/d^2
K- Constant ( is your gradient)
What is the photoelectric effect evidence for ?
It is evidence for light being a particle
What is the work function?
The minimum energy of a photon required to cause the emission of photoelectrons from a metal surface.
What is threshold frequency?
Threshold frequency is the minimum frequency a photon must have to eject an electron from the metal.
To find the speed of a particle what can you do ?
Set W=QV equal to Ek= 1/2mv^2
W - Work done by the field
Q - Charge in coulombs
V- Voltage across field
What is the energy of a single photon of light proportional to ?
It’s frequency
What is the symbol for direct proportion similar to ?
Symbol for alpha
What does incident mean ?
Incident is used to describe particles or radiation that fall on a surface.
What is the calculation for the energy of a photon ?
E=hf E- Energy of photon h - Planck's Constant f - Frequency of the light ( v=frequency x wavelength)
What is the work function formula?
E=hfo
E- Energy
h- Plancks constant
fo- threshold frequency of the metal
What formula can you use to find kinectic energy?
Ek= hf-hfo
Ek - Kinetic energy
hf- Energy of photon
hfo- Work function
What happens to the number of electrons being ejected when you up the irradiance of UV light
It increases
What are the Irradiance formulas
Id^2= Id^2 ( Point source of light)
Id^2 = constant
I=P/A
What is a point source of light
A point source of light is a light source in which the light is emitted equally in all directions.
Why does a Linear particle accelerator and Cyclotron require ac supplies?
when particles pass an electrode to which they are being attracted, the electrode switches charge, and starts to repel the particle. Otherwise the particle would remain stationary
What happens to the mass lost in Nuclear fission and fusion reactions
Mass lost is converted to energy
E=mc^2
what happens when matter and anti-matter meet
They are destroyed and produce energy.
What is the Range of a Photon?
Photon is responsible for electromagnetism. (Keeps electrons in orbit around an atom)
Range is Infinite
What is the range of W and Z Bosons?
W and Z Bosons are responsible for the weak nuclear force that allows beta decay ( Turns neutrons into protons and vice versa)
Range is across the nucleus (x10^-18m) - Smallest range of the bosons
What is the range of a gluon?
Gluon is responsible for the strong force . ( Holds protons together in the nucleus)
It’s range is x10^-15m.
