Electricity Formulas

Electricity Formula

Electricity is the flow of charge in a conductor from anode to cathode. Electricity has several applications. It functions as a power source for electrical gadgets. We can say that charge flow generates a current, or electricity. To comprehend how electricity is generated, we must first grasp the basic factors related with it, such as voltage, current, resistance, and conductivity, as well as their relationships.

What is Electricity Formula?

The passage of charge in a conductor from anode to cathode is defined as electricity. Electricity has many different applications. It serves as a power source for electrical equipment. Students may say that the movement of charge generates current, which students call electricity. To comprehend how electricity is created, they must first grasp the numerous fundamental factors associated with it, such as voltage, current, resistance, conductivity, and their relationships.

What is Electricity?

Electricity and current are both linked concepts. As students all know, all charges, whether free or bound, are regarded at rest. During motion, these charges will form an electric current.

Such currents occur naturally in a wide range of real-world conditions. Lightning is one example of the phenomenon in which charges move through the atmosphere from the clouds to the earth.

Only the movement of charges causes an electric current to occur. Positive and negative charges may both go forward and backwards. Conductors are an excellent electrical medium. If an electric field is applied, an electric charge will experience force. The current is the same for all cross-sections of a non-uniform cross-section conductor.

Ohm’s Law is a fundamental law governing the flow of currents. Both resistivity and conductivity are connected concepts that may be estimated with the assistance of others.

Furthermore, the power of electricity may be simply calculated. The electromotive force, or emf, of the source, is the work done per unit charge by the source when moving the charge from a lower to a higher potential.

Some Important Electricity Formulas

The Electricity formulas are the physical occurrence of the presence and movement of electric charge. To understand how electricity is created, electrons are loosely packed by the nucleus and travel freely inside the body. Because they are negatively charged particles, when they produce multiple charges, the movement is known as electric current or electricity.

Quantity Formulas Unit
Current I I = Q / tQ = Charge

t = time taken

Amperes (A)
Voltage V V = E / Qor

V = W / Q

E = Energy, W = Work done

Volts (V)
Resistance R R = ρl / Aρ = Resistivity,

l = length,

A = Area


R = V / I

Ohm (Ω)
Power P P = VI Watts (W)
Conductivity σ sigma = 1 / ρ Siemens per meter (S/m)

Electricity and its Effect (notations)

Physical Quantity Symbols SI unit
Voltage (potential difference) V Volt(V)
Power P Watt(W)
Charge Q Coulomb (C)
Work or Energy W Joule (J)
Resistance R Ohm Ω
Current I Ampere (A)
Resistivity ρ Ohm metre (Ω m)

Solved Examples

Example 1 : An electric heater has a potential difference of 220 V and a resistance of 11 Ω. Determine the magnitude of the current that passes through it.



Resistance R = 11 Ω

Voltage V = 220 V

The current formula is given by

I = V / R

= 220 / 11

I = 20 A

Example 2 : An electrical lamp lights for 6 hours and draws a current of 0.3 A. Find the amount of charge flowing through the lamp.


Current I = 0.3 A

Time taken t = 6 hours

t= 6 × 3600 = 21600 s,

Charge Q = I × t

= 0.3 ×21600

Q= 6480 C

Physics Related Formulas
Electric Field Formula Poynting Vector Formula
Gross Profit Formula Refraction Formula
Mass Formula Sound Intensity Formula
Capacitance Formula Uniform Circular Motion Formula
Centripetal Force Formula Thermal Expansion Formula
Distance Speed Time Formula Thermal Energy Formula
Ohms Law Formula Amperes Law Formula
Refractive Index Formula Horsepower Formula
Wavelength Formula Lattice Energy Formula
Stress Formula Length Contraction Formula

FAQs (Frequently Asked Questions)

1. What is the formula for calculating current?

The formula for calculating current is –

I = Q / t

where I is current, Q is charge, and t is time taken.

2. What is the formula for resistance?

The formula for resistance is –

R = ρl / A or R = V / I

where R is resistance, ρ is resistivity, l is length, A is area, V is voltage, and I is current.

3. How is voltage calculated?

Voltage can be calculated using the formula

V = E / Q or V = W / Q

where V is voltage, E is energy, W is work done, and Q is charge.