# AP Physics Formulas (Electricity and Magnetism)

## 17 terms

### Finding Electric Field

E = F/q

Electric field (E) is equal to the force (F) divided by the charge (q).

### Finding Potential Energy of an Electric Field

UE = qV

The potential energy of an electric field is equal to the charge (q) times the potential difference (V).

### Finding Average Electric Field

Eavg = -V/d

Average electric field is equal to the negative potential difference (-V) divided by the distance (d).

### Finding Capacitance

C = Q/V

Capacitance (C) is equal to the charge (Q) divided by the potential difference (V).

### Finding Capacitance

C = ε₀A/d

Capacitance (C) is equal to the electromotive force (emf, ε₀) times the area (A) all divided by the distance (d).

### Finding Potential Energy of a Capacitor

Uc = 1/2QV = 1/2CV²

The potential energy of a capacitor is equal to one-half of the charge (1/2Q) times the potential difference (V) which is equal to one-half of the capacitance (1/2C) times the potential difference squared (V²).

### Finding Average Current

Iavg = ΔQ/Δt

Average current (Iavg) is equal to the change in charge (ΔQ) divided by the change in time (Δt).

### Finding Voltage of a Circuit

V = IR

Voltage (V) is equal to the current (I) times the resistance (R).

### Finding Power of a Circuit

P = IV

Power (P) is equal to the current (I) times the Voltage (V).

### Finding Equivalant Capacitance with a Series Circuit

1/C = 1/C₀ + 1/C₁

The inverse of equivalent capacitance (C) in a series circuit is equal to the sum of the inverse of each capacitor (1/C₁, 1/C₂).

### Finding Equivalent Capacitance with a Parallel Circuit

C = C₀ + C₁

Equivalent capacitance (C) in a parallel circuit is equal to the sum of each capacitor (C₀, C₁).

### Finding Equivalent Resistance with a Series Circuit

R = R₀ + R₁

Equivalent resistance (R) in a series circuit is equal to the sum of each resistor (R₀, R₁).

### Finding Equivalent Resistance with a Parallel Circuit

1/R = 1/R₀ + 1/R₁

The inverse of equivalent resistance (R) in a parallel circuit is equal to the sum of the inverse of each resistor (1/R₁, 1/R₂).

### Finding Magnetic Force on a Point Charge

FB = qvBsin(Θ)

Magnetic force (FB) is equal to the charge (q) times the velocity (v) times the strength of the field (B) times the sine of theta (sin(Θ)). Note: The sine of 90 is 1.

### Finding Magnetic Force on a Current-Carrying Wire

FB = BILsin(Θ)

Magnetic force (FB) is equal to the strength of the field (B) times the current (I) times the length (L) times the sine of theta (sin(Θ)). Note: The sine of 90 is 1.

### Finding Magnetic Flux

∅m = BAcos(Θ)

Magnetic flux (∅m) is equal to the strength of the field (B) times the area (A) times the cosine of theta (cos(Θ)). Note: The cosine of 0 is 1.

### Finding EMF

ε = BLV

Electromotive force (emf, ε) is equal to the strength of the field (B) times the length (L) times the potential difference (v).