All Flashcards
Ground state hydrogen energy
-E_1=ł^2 / (2 m a^2)=k^2 m e^4 / (2ł^2)
Bohr radius
a=ł^2 / (k m e^2)
Electric constant k=1/(4 pi e_0)
10^10 Н м^2/Кл
How does the ground state energy of a hydrogen-like atom depend on Z?
E_1 ~ Z^2
1 Henri in terms of seconds
H=V s^2 / C=В с^2 / Кл
1 Ohm in terms of seconds
Ohm = V s / C = В с / Кл
1 Farade in terms of other units
F = C / V = Кл / В
h c = ? eV nm
1240
ł c = ? eV nm
200
k_b * 300 K = ? eV
0,026 = 1/40
Mass of a proton
938 MeV/c^2
Atomic mass unit (carbon/12)
931 MeV/c^2
Rydberg constant
R = -E_1/hc = 1.1*10^7 m^(-1)
Rydberg formula for hydrogen emission
1/lambda = R ( 1/m^2 - 1/n^2 )
Fine structure constant
alpha = k e^2 / (łc) = 1/137
Second order perturbation correction to energy levels
E_n^1 = E_n + + Sum ||^2 / (E_n - E_m)
Wien displacement law
Lambda_max = 3 / T (mm)
Lorentz transformation matrix from x to x’
Gamma -gamma beta 0 0
-gamma beta Gamma 0 0
0 0 1 0
0 0 0 1
Energy-momentum vector
(E/c, p)
Charge-current vector
(c rho, j)
Wave four-vector
(omega, c k)
Square of the energy-momentum vector = ?. Invariant? Conserved?
m^2 c^2 in any reference frames. Invariant and conserved.
Relativistic energy in terms of the rest energy
E = gamma m c^2
Relativistic momentum in a non-rest frame
p = gamma m v
Doppler frequency shift in classical waves
(v + v_rec) / (v - v_source) where v is the speed of waves
Relativistic Doppler frequency shift
Sqrt(1+beta/1-beta)
Compton wavelength shift
D_lamda=h/mc (1-cosO)
Table of quarks
u c t. 2/3
d s b. -1/3
e mu tau
ne nmu ntau
Proton and neutron quark formulas
p=uud
n=udd
Fermi energy
k_f = (3 pi^2 n)^1/3 E_f = ł^2 k^2 / 2m
Density of states
g(E) = (V Sqrt(2) / (pi^2 ł^3)) m^(3/2) Sqrt(E)
Density of states at Fermi surface
g(E_f) = 3N / 2E_f
Solenoid inductance
L = mu_0 N^2 A / l
When moving with constant acceleration, what time does it take to go dx if the terminal velocity is v?
dt = 2dx/v
When moving with constant acceleration a, how does the square velocity change over distance dx?
d(v^2) = 2 a dx
How does the amplitude of driven oscillations depend on the frequency?
A ~ 1/|w^2 - w0^2|
The potential of an electric dipole
U = k (p,r) / r^3
Electric field of a dipole
E = k r (p,r) / r^5 - k p / r^3
Torque on a dipole
M = p x E M = m x B
Radiation intensity of an oscillating dipole with amplitude p0 and frequency w.
<i> ~ p0^2 w^4 (sinO/r)^2</i>
The total power emitted by an oscillating dipole
<p> = mu0 p0^2 w^4 / (12 pi c),
| c^2 times less for a magnetic dipole.
</p>
Energy of a capacitor
W = U^2 C / 2 = Q^2 / 2C
Energy of an inductor
W = I^2 L / 2
Time constants of RL and RC circuits
tau = L/R and RC
High pass filter
o-----||----------o | R \_\_|\_\_ ---