不得不说又是一个丢脸的贴，国内的大学同学肯定早在2年前就搞完这些东西了。但为了毕业我还是需要修这么一个课。而且，知识永远也不嫌少，发个总结贴总是比学过就忘要好的，这是从0到1的进步。

Some simple facts from practice exam questions:
(Please include related formulas upon future update)
·Field lines point away from positive charge and toward negative charge.
·In a circuit, capacitors in series have the same charge on them and capacitors in parallel have the same potential drop across them.
·A charged particle that is moving against a magnetic field (in the opposite direction as the field) will move in a straight line.
·Two parallel wires with currents running in the opposite direction repel each other.
·A loop is turned in a magnetic field to generate electricity. As the loop is rotated faster, the induced voltage increases.I

About Polarization:
When unpolarized light go through a linear polarizer(looks like a disk), its intencity cut in half.
If it go through another one again, Ｓ = Ｓ0 Cos²θ 【Malus' Law】
About RLC circuit:
Inductance(L): ＸL = 2πf·L
Capacitance(C): ＸC = 1 / 2πf·C
Impedance of the whole circuit: Ｚ² = (ＸL - ＸC)² + Ｒ²I

About RLC circuit:
Q: What is the average power dissipated in the circuit?
Use average U or I, and the resistor R to calculate P.
Ｕ/Ｉaverage = Ｕ/Ｉmax ÷√2

___________ \____________
|　　　　　　　|　　　　＝ [Capacitor]
[Power]　　　　Ｒ1　　　|
|______________|________Ｒ2
Q: Calculate the current through the battery right after the switch is closed.
A: Ignore the capacitor as if it wasn't there.
Q: Calculate the current through the battery after the switch has been closed a long time.
A: Ignore the whole loop of capacitor as if there wasn't a Ｒ2. The reason is, after a long time the capacitor would be fully charged. In such cases, no current flows through it.I

Multiple capacitors within a circuit:
Power Source: U = 9V
Main loop: Ｃ1 = 1μF
Loop 1: Ｃ2 = 2μF
Loop 2: Ｃ3 = 3μF, Ｃ4 = 4μF
Important Formula: U = Q/C
Q: What is the charge on capacitor C1?
A: Ｑtotal = Ｑ1 = Ｑ234(I'm a bit confused about this though, but that's how it works out. See part of the reason below)
There is an very important difference between calculating the total R of resistors and total Q of capacitors: do it exactly the opposite way. When two Cs are in parallel, you add them up! When they are in series, you use the < AB/(A+B) > method instead.
K: 7.09μC
Q: What is the potential difference across capacitor C3?
A: By U = Q/C, you figure out Ｕ1 = 7.09V. Therefore Ｕ234 only have 1.91V left. And Ｕ2 = Ｕ34 = 1.91V as they are in parallel.
Notice that the distribution of Uon Cs within one loop works oppositely as it does on Rs, as U = IR = Q/C. U is larger when C is smaller, so [ 1.91V × 4/7 ] is the anwser.
K: 1.09 V
I

How to calculate the magnitude of net electric field at a specific point, while there are several charges around:
A: E = kQ/R²
in which:
k = 8.99×10^9 Nm²/C² （Coulomb's constant）
Q = charge(C)
R = distance(m)
The result of E would be one charge's "effect" on that point, like a force. Yes, they are vectors! Combining them like calculating the net force.
A positive charge will have a positive "effect", like pushing the point. A negativeone would be pulling.
How to calculate the electric potential at a specific point:
A: Kind of like calculating the magnitude, but the potentials are NOT vectors.
Use this equation: U = kQ/R
And directions do not count! You only have to add up the numbers(positive and negative) you got.
(Perhaps the result could be negative, not sure yet.)
I

Parallel Plates Capacitors:
C = ε0·A/d
Units: Farads(F)
ε0 = 8.85×10^-12 F/m

◆Magnetic Field's Effect
▶Force on a charged moving particle:
·F = qvB sinθ
·R = mv/qB
▶Force on a length of current:
·F = IlB sinθ
▶Direction about particle:
Using either hand
Thumb - charge's moving direction
Palm - Opposite of magnetic field's force on it
Other fingers - Direction of the field
▶Direction about current:
Using right hand
Thumb - Direction of current
Palm - Direction of magnetic field's force on it
Other fingers - Direction of the field
◆Magnetic Field Created by Current
Ｂ = μ0Ｉ/２πＲ
μ0 = 4π×10^(-7) T-ｍ/A
I

◆Motional EMF
When a conducting loop pass through a magnetic field:
Force on the electrons push them to move! Therefore a current is generated.
Faraday's Law:
ε = -ΔΦ/Δt
(Remember what ε stands for? The result would be in V.)
in which：
Φ is magnetic flux.
Φ = BA·cosφ
`φ is the angle between the direction of the field and that of the area.I

What is resonance in a RLC circuit?
A: It occurs when the impedance(Z) is at its minimum, which means, ＸL = ＸC.

Optics
◆ About image in a concave mirror - image height, distance to the mirror and focal length, that sort of stuff:
The mirror equation
1/ｄo + 1/ｄi = 1/ｆ
in which:
ｄo stands for the distance from the object to the mirror;
ｄi stands for the distance from the image to the mirror;
ｆ stands for the focal length.
(the image in the mirror - but as you know, in physics you should treat it like the image is on the other side of the mirror)
With this equation you can calculate stuff such as where the image would be if you move the object.

Relativity and Radioactivity:
◆In this sort of problem:
Thorium (with half-life T1/2 = 1.913 yr. and atomic mass 228.028715 u) undergoes alpha decay and produces radium (atomic mass 224.020186 u) as a daughter nucleus. (Assume the alpha particle has atomic mass 4.002603 u.)
If you want to calculate the amount of energy the decay produce, there is an very important thing you need to pay attention to!
The differences of mass you got, only a tiny part of it directly transform to energy, otherwise the energy will be too huge.
So how big is that part? It is represented by "mass loss per atom" when emitted. It is calculated by [(228.028715 - 224.020186 - 4.002603)/228.028715].