MCAT Physics Equations and Constants to Know

Elementary charge

e = 1.6 x 10^19 C

Coulomb’s Law

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Coulomb’s constant

k = 9 x 10^9 N•m^2/C^2

Electric force on a charge

F(e) = qE

Electric field created by a point charge

E = (k|Q|) / r^2

Electric potential at a point

Φ = (kQ) / r

Electric potential energy

∆PE(e) = q∆Φ = qV

Voltage of battery

V = ∆Φ

Capacitance

C = (kε(o))(A/d)

Charge on a capacitor

Q = CV

Energy stored by a capacitor

PE = 1/2(QV) = 1/2CV^2 = (Q^2)/2C

Electric field in a capacitor

V = Ed

Capacitance enhanced by dielectric

C = kC(o)

Flow rate of charge

I = ∆Q/∆t

Ohm’s Law

V = IR

Resistance and resistivity

R = rho (L/A) ; R = resistance, rho = resistivity

Resistance for resistors in series

R(eq) = R(1) + R(2) +…

Capacitance for capacitors in series

1/(C(eq)) = 1/(C1) + 1/(C2) + …

Resistance for resistors in parallel

1/(R(eq)) = 1/(R1) + 1/(R2) +…

Capacitance for capacitors in parallel

C(eq) = C(1) + C(2) + …