Electricity Equations
Electricity is the branch of Physics that is dedicated to the study of phenomena of an electrical nature. The equations are divided between Electrostatics and Electrodynamics.
See the definition of each Electricity subdivision and the main equations used:
→ Electrostatics
In this field of study, all electrical phenomena occur with electrical charges at rest.
- electrical load
Q = Electric charge (C – coulomb);
n = Number of elementary charges;
e = Elementary charge (e = 1.6 x 10 – 19 C).
- Electric force – Coulomb’s Law
F = Electric force (N – Newton);
Q 1 and Q 2 = Electric charges (C);
d = Distance between electrical charges (m);
K = Electrostatic constant in vacuum (k = 9.0 x 10 9 Nm – 2 C – 2 ).
- Electric field
E = Electric field (N/C);
F = Electric force (N);
q = Test electrical charge ©.
E = Electric field (N/C);
K = Electrostatic constant in vacuum (k = 9.0 x 10 9 Nm – 2 C – 2 );
Q = Electric charge generating the electric field (C);
d = Distance between the electric charge and any point (m).
- electrical potential energy
E P = Electric potential energy (J);
K = Electrostatic constant in vacuum (k = 9.0 x 10 9 Nm – 2 C – 2 );
Q eq = Electric charges (C);
d = Distance between electrical charges.
- Electric potential
V = Electric potential (V – volts);
K = Electrostatic constant in vacuum (k = 9.0 x 10 9 Nm – 2 C – 2 );
Q = Electric charge (C);
d = Distance between the electric charge and any point (m).
→ Electrodynamics
In Electrodynamics, electrical phenomena occur with moving electrical charges. The orderly movement of electric charges is called electric current.
- Electric current
i = Electric current (A = ampere);
Q = Electric charge (C);
Δ t = Time interval considered for the flow of electric charges (s).
- Ohm’s Laws
U = Electric potential difference (V);
R = Electrical resistance (Ω – ohm);
i = Electric current (A).
R = Electrical resistance (Ω – ohm);
ρ = Resistivity (Ω .m);
L = Length of conductive material (m);
A = Cross-sectional area (m 2 ).
- Combination of resistors in series
i = Electric current (A);
U = Potential difference (V);
R = Electrical resistance (Ω – ohm).
- Connecting resistors in parallel
i = Electric current (A);
U = Potential difference (V);
R = Electrical resistance (Ω – ohm).
- Joule effect
Q = Amount of heat (cal – Calories);
i = Electric current (A);
R = Electrical resistance (Ω – ohm);
Δ t = Time interval (s).
- Electric power
Pot = Electric power (W – watts);
i = Electric current (A);
U = Potential difference (V);
R = Electrical resistance (Ω – ohm).
- Energy consumed
E = Energy consumed (kWh – kilowatt-hour);
Pot = Power of electrical equipment (kW);
Δ t = Time interval (h).