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GRE Physics

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Mech: Force of Friction
X_L = i?L
µ0 I / 2pR
F_f = µ*F_N
1/2 CV²

2. Bar magnets -- direction of B field lines - earth'S B field
E = Z²*E1
ma + kx = 0
North to south; Earth has S magnetic pole at the N geographic pole and vice versa.
P1V1 - P2V2 / (? - 1)

3. Effective Potential
In Zeeman effect - the contribution of electron spin to total angular momentum means that it isn'T always three lines and they are not always equally spaced.
V(r) + L²2/2mr²
F = s * T4
?mc²

4. Perpendicular axis theorem
I_z = I_x + I_y (think hoop symmetry)
Infinitely close to equilibrium at all times
Const: 2t = (n +.5)? Destructive 2t = n?
ds² = (c*dt)² - ?(x_i)²

5. Bernoulli Equation
Exponentially decreasing radial function
qvb = mv²/R
P +1/2 ? v² + ?gh = Constant
(3/2) n R ?t

6. Selection Rules
E = Z²*E1
?s = 0 - ?l = ±1
PdV +dU
S = k ln[O] ; dS = dQ/T

7. Work done on a gas
DW = P dV
1s² - 2s² 2p6 - 3s² 3p6 3d¹°
Dp/dt = L / (t ?V)
qvb = mv²/R

8. Atom: Bohr Theory Ionization
E = Z²*E1
Faraday/Lenz: current inducted opposes the changing field
Infinitely close to equilibrium at all times
X_L = X_C or X_total = 0

9. Focal point of mirrror with curvature
L = µ N² A / l : N = number of turns - A = cross sectional area -l = length
H = H_0 + ?H
u dm/dt
F = R/2

10. Mech: Centripetal Force
Measurements close to true value
F = mv²/r
P/A = s T^4
ma + kx = 0

11. Solid: Resistivity of Semi-Conductor
J = E s - s = Conductivity - E = Electric field
T^2 = k R^3 - k=constant
F = I L X B
?~1/T

12. Dulong Petit Law
T^2 = k R^3 - k=constant
Z_c = -i/(?C) ; Z_L = i ? L
Cv = dE/dT = 3R
DS = 0 - dQ = 0 - P V^? = constant

13. Work in a capacitor
F = qv×B
?scl = +/-1;?m = 0 - +/-1;?S_tot = 0;(?j = ?scl + ?S_tot)
?mc²
1/2 CV²

14. Doppler shift for light
L = T - V dL/dq = d/dt dL/dqdot
? = ?_0 Sqrt[(1+v/c)/(1-v/c)]
DS = 0 - dQ = 0 - P V^? = constant
1/2 CV²

15. Doppler Shift for light
L = mr²d?/dt
?max = 2.898 x 10 -³ / T
? = ?0 root((1-v/c)/(1+v/c))
4H + 2e- ? He +2? + 6?

16. Atom: Orbital Config
E = Z²*E1
? = 1.22? / d
1s² - 2s² 2p6 - 3s² 3p6 3d¹°
H = H_0 + ?H

17. Mech: Impulse
? = 5/3
µ = m_e/2
B = µ0 I n
J = ? Fdt

18. Force on a wire in magnetic field
F = I L X B
Let w_i = 1/s_i^2;x_wav = S(w_i x_i) / Sw_i - s_xwav = 1/Sw_i
?mc²
Infinitely close to equilibrium at all times

19. Compton Scattering
I = V/R exp(-t/RC)
D/dt (.5*r^2 d?/dt) = 0 - r(?) = a(1-e²)/(1+ecos(?)) - T²aA³
Sin(?) = ?/d
?? = h/mc * (1-cos(?))

20. Internal Energy of an Ideal Gas
(3/2) n R ?t
<T> = 1/2 * <dV/dx>
I = I_cm + (1/2)m d^2
E_n = -µ c^2 Z a^2 / (2n^2) - with µ = m_1 m_2 / (m_1 + m_2)

21. Magnetic Field of a long solenoid
Asin(?) = m?
NC?T
L = L_0 Sqrt[1-v^2/c^2]
B = µ0 I n

22. Mech: Rotational Energy
In Zeeman effect - the contribution of electron spin to total angular momentum means that it isn'T always three lines and they are not always equally spaced.
T = I?²/2
P(s) = (1/Z) Exp[-E(s)/(k T)] Z = S_s(Exp[-E(s)/(k T)])
Z = ?g_i*exp(-E/kT)

23. Energy in Inductor
dU = 0 ? dS = ?dW/T
Ct²-x²-y²-z²
0
.5 LI²

24. Spherical Capacitor Equation
F = -2*m(? x r)
C = 4pe0 ab/(a-b) = inner and outer radii
Measurements close to mean
Triplet: symmetric - net spin 1 Singlet: antisymmetric - net spin 0

25. EM: Electric Field inside of Conductor
0
1. Heat is energy 2. Entropy never decreases 3. Entropy approaches a constant value as t -> 0...
µ0 I1I2 / (2pd)
E = <?| H |?>

26. Triplet/singlet states: symmetry and net spin
V = V0 + V0 a ?T
E = Vmin : circle - E = 0 : parabola - E<0 : el - E>0 : h
Triplet: symmetric - net spin 1 Singlet: antisymmetric - net spin 0
qvb = mv²/R

27. Lagrangian and Lagrange'S equation
1s² - 2s² 2p6 - 3s² 3p6 3d¹°
L = T - V dL/dq = d/dt dL/dqdot
C_eq = (? 1/C_i)^-1
V(r) + L²2/2mr²

28. Self Inductance
V = -L di/dt
?mv
N²/Z (m_elec/m_red)
? = 1.22?/D

29. Coriolis Force
F = -2*m(? x r)
Cv = dE/dT = 3R
Dv = -udm/m - v = v0 + u ln(m0/m)
C = 4pe0 ab/(a-b) = inner and outer radii

30. EM: Parallel Capacitance
C_eq = ?C_i
Faraday/Lenz: current inducted opposes the changing field
µ0 I / 2pR
Product ( nj ^ vj ) = Product(nqj ^ vj exp (-vj F(int)/Tau))

31. Expectation value of the energy of state |?>
IR + Ldi/dt = 0 - I = I0e(-tL/R) Work = 1/2 L I0^2
E = <?| H |?>
A[B -C] + [A -C]B
J = ? Fdt

32. Hall Coefficient
Hbar*?³/(p²c³exp(hbar?/t)-1)
qvb = mv²/R
(° of Freedom)kT/2
1/ne - where n is charge carrier density

33. Thermo: Monatomic gas ?=?
? = 5/3
(3/2) n R ?t
Measurements close to mean
qvb = mv²/R

34. Relativistic Energy
DW/dq
1/ne - where n is charge carrier density
1. Heat is energy 2. Entropy never decreases 3. Entropy approaches a constant value as t -> 0...
?mc²

35. Astro: Kepler'S Third Law
<?|O|?>
B = µ0 I (sin(?1)-sin(?2))/(4pr) r = distance from point
P² ~ R³
µ0 I / 2pR

36. Radiation (Larmor - and another neat fact)
P = µ_0 q^2 a^2/(6Pi c); No radiation along the axis of acceleration
.5 CV²
P(s) = (1/Z) Exp[-E(s)/(k T)] Z = S_s(Exp[-E(s)/(k T)])
NC?T

37. De Broigle Wavelength
? = h/mv
S = (hbar/2) s ;with S = S_x xhat + S_y yhat + S_z zhat -s = s_x xhat + s_y yhat + s_z zhat
µ0 I / 2pR
E ~ (1/(n_f)² - 1/(n_i)²) ~ 1/?

38. Current in resistor in RC circuit
B = µ0 I (sin(?1)-sin(?2))/(4pr) r = distance from point
E = Z²*E1
E = s/e_0
I = V/R exp(-t/RC)

39. Angular momentum - Central Force Motion
W' = (w-v)/(1-w v/c^2) ; observer in S sees an object moving at velocity w; another frame S' moves at v wrt S.
Series: 1/k_eq = 1/k_1 + 1/k_2; Parallel: k_eq = k_1 + k_2
L = mr²d?/dt
S = (hbar/2) s ;with S = S_x xhat + S_y yhat + S_z zhat -s = s_x xhat + s_y yhat + s_z zhat

40. Lensmaker Equation - Thin Lens
1/f = (n-1)(1/R1 - 1/R2) if both positive - they are convex - concave
Opposing charge induced upon conductor
?? = h/mc * (1-cos(?))
P² ~ R³

41. Source-free RC Circuit
W_A < W_I
X_C = 1/(i?C)
0
CdV/dt + V/R = 0 V(t) = V0 exp(-t/RC) I(t) = I(0) exp(-t/RC)

42. td(entropy) =
I_z = I_x + I_y (think hoop symmetry)
D/dt (.5*r^2 d?/dt) = 0 - r(?) = a(1-e²)/(1+ecos(?)) - T²aA³
PdV +dU
µ0 I / 2R

43. Thermo: Adiabatic Work vs Isothermal Work
W_A < W_I
DS = 0 - dQ = 0 - P V^? = constant
? = 5/3
F = R/2

44. Bragg'S Law of Reflection
F = s * T4
U - ts = -tlog(Z)
M? = 2dsin(?)
.5 CV²

45. Mech: Virial Theorem
I = I_0 Cos[?]^2
Cos[?] Sin[?] -Sin[?] Cos[?]
CdV/dt + V/R = 0 V(t) = V0 exp(-t/RC) I(t) = I(0) exp(-t/RC)
<T> = -<V>/2

46. Entropy (# of states - and in terms of other thermo quantities)
1/f = (n-1)(1/R1 - 1/R2) if both positive - they are convex - concave
S = k ln[O] ; dS = dQ/T
div(E) = ?/e_0 - curl(E) = der(B)/der(t) - div(B) = 0 - curl(B) = µ_0J + µ_0e_0*der(E)/der(t)
Z = ?g_i*exp(-E/kT)

47. Kepler'S Three Laws
D/dt (.5*r^2 d?/dt) = 0 - r(?) = a(1-e²)/(1+ecos(?)) - T²aA³
Braking Radiation
<T> = 1/2 * <dV/dx>
L = mr²d?/dt

48. EM: AC Resonance
L = L_0 Sqrt[1-v^2/c^2]
X_L = X_C or X_total = 0
E_n = -µ c^2 Z a^2 / (2n^2) - with µ = m_1 m_2 / (m_1 + m_2)
F_f = µ*F_N

49. Rocket Thrust
Ct²-x²-y²-z²
E = Z²*E1
<T> = -<V>/2
u dm/dt

50. Charge in Capacitor
Q = CVexp(-t/RC)
<?1|?2> = 0 ? Orthogonal
Cos[?] Sin[?] -Sin[?] Cos[?]
Infinitely close to equilibrium at all times