Physics Equations “circuits” MCAT
circuits
Voltage = IR (Ohm’s Law)
R = resistance
I = current
Capacitance = Q / V Q = CV
Q = charge
V = voltage
**Capacitance is the ability to store charge per unit voltage**
The energy stored within a capacitor can be found using these equations:
U = .5(QV)
U = .5(C)(V^2)
U = .5(Q^2) / (C)
Resistors
Total resistance for resistors in series: R(eff) = R1 + R2 + R3 …….
Total resistance for resistance in parallel = 1/R(eff) = 1/R1 + 1/R2 + 1/R3……
Capacitors
Total capacitance of capacitors in series: 1/C(eff) = 1/C1 + 1/C2 + 1/C3 …
Total capacitance of capacitors in parallel: C(eff) = C1 + C2 + C3 …..
Electric Power
P = IV
P = I^2(R)
P = V^2/R
magnetism
F = qvBsin(theta)
F = force on the charge moving through the magnetic field
q = charge
B = magnetic field
**Note that the force is directed perpendicular to both the velocity and the magnetic field**
Alternating Circuits
V(max) = sqrt(2) rms
I(max) = sqrt(2) rms
