E+B fields Flashcards
Potential energy moving in a point charge field
W=kQq/r
Derivation for charge stored on capacitor
add a small change in Q and multiply by V to find additional energy stored,
Results in W=1/2QV
Force on a particle in a B field F=
F = Bqv
B = field strength
q = charge in field
v = velocity of particle
Lenz’s law and when is applicable
The ‘back emf’ from faraday’s law will tend to oppose the change that caused it
In a closed cicruit or on a conductive material.
Capacitance equation
C=Q/V
Acronym for circular acceleration derivation
VStv
Vector
Sin
time (divide)
v = wr (formula book)
Rutherford scattering observations
Most go straight through
Atom is mostly empty space
Some are deflected by small angles <90
Atom has a concentration of positive charge in nucleus
Few are backscattered by >90
Small and massive positively charged nucleus
Thermionic emission
thermal energy given overcomes work function
Particle accelerator energy transfer
QV = 1/2mv^2
eletrcial energy = kinetic
How does a linear particle accelerator accelerate
Series of tube electrodes with alternating PDs (attatched to ac supply) so alternating E fields, repels from previous tube and accelerates to next tube.
why do LINACs increase in length as you go along tubes
so the particle spends the same ammount of time in each tube as the last one.
(ac hooked up to specific frequency and so particle must be in the right tube at the right time)
Cyclotrons structure
Two semicurluar ‘dees’ with uniform, alternating E fields, will accelerate a particle, F=Eq.
Uniform B field at right angles (up or down) to provide centripetal force F=Bqv.
As accelerated p ^ as p=Bqr, r increases so goes closer to edge, when p high enough r high enough for particle to leave accelerator.
Derive r=p/Bq
F=Bqv and F=mv^2/r
Standard model deifinitions
Baryons - qqq or anti
Mesons q anti q pair
Leptons- electrons, muons etc.
As you get into higher generations..
Mass increases
