Electric Charge Formula: Definition, Coulomb’s Law, Role, and Sample Questions

Electric Charge Formula Overview

The property of a unit of matter known as an electric charge defines how many more or fewer electrons than protons it has. Electric charge aids in measuring the process by which we may gauge the strength of an object's electric field. The idea of an electric charge was developed as a result of studying electrostatic events. The letter Q is used to represent an electrical charge, also known as an electrical charge or an electrostatic charge.

What is an Electric Charge?

When put in an electromagnetic field, matter experiences a force due to its physical characteristic known as an electric charge. One might have a positive or negative electric charge (commonly carried by protons and electrons, respectively, by convention). Unlike charges attract one another, while like charges repel one another. Neutral refers to an item that has no net charge. Classical electrodynamics, the name given to an early understanding of how charged particles interact, is still true for issues that do not demand taking into account quantum phenomena.

Electric Charge Formula Highlights

The following table gives details about the electric charge formula-

What is Electric Charge Formula?

The electric charge formula is as follows-

Q = I x t

Where, 

Q = Electric Charge

I = Electric Current

t = Time 

Role of Electric Charge in Electric Current

The movement of electric charge through a material is known as electric current. Any of these charged particles moving around creates an electric current. When referring to the conventional current, it is often sufficient to say that it is carried by positive charges flowing in the conventional current's direction or by negative charges moving in the opposite direction. The electromagnetic principles and computations are approximated from a macroscopic perspective. The flow of electrons, the flow of electron holes, which behave like positive particles, and the flow of both negative and positive particles (ions or other charged particles) flowing in opposite directions in an electrolytic solution or a plasma are three examples of how an electric current can be carried.

Note: Be aware that the direction of conventional current in the common and significant case of metallic wires is the opposite of the drift velocity of the real charge carriers, i.e., the electrons. Beginners often get confused with this.

Read more about Electroscope.

Coulomb's Law of Electric Charge Formula

The SI unit of charge is known as the"coulomb," and it is named for the French scientist Charles-Augustin Coulomb. The meaning of one Coulomb is the amount of charge that one ampere of current can move in one second is measured in Coulombs.  One Coulomb of charge contains around 6 × 10¹⁸ electrons.

1 C = 6 × 10¹⁸ electrons

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Points to Remember

1. The number of electrons or energy transported from one body to another by various modalities, including induction, conduction, etc., is known as the electric charge.
2. The charge is always represented by the letter "Q," and the Coulomb is used to describe it.
3. The electric charge has the following characteristics: it is a scalar quantity, it is related to mass, it can be transferred, it can be quantized, and it is invariant.
4. A body may be charged in three different ways: through friction, conduction, and induction.
5. The amount and direction of the entire electrical force shown by one unit of electric charge are represented mathematically as the electric field.

Read more about Electrical Insulator and EMF Equation of DC Generator.

Sample Questions for Electric Charge Formula

Sample Question 1- A conductor carries a current of 0.6 A. In 37 seconds, how much charge will flow through the conductor's cross-section?

Solution: Given,

I = 0.6 A

t = 37 s

Since,

Q = I × t

Q = 0.6 × 37

Therefore, 

Q = 22.2 C

Sample Question 2- Find the electric charge if the electric current is 200 A and the time is 3 minutes.

Solution:Q = I × t

Q = 200 × 180

Therefore,

Q = 36000 C

Sample Question 3- During two minutes, a 150 mA circuit is operated. determine the flow of charge through a circuit.

Solution: Given, 

I = 150 mA = 150 × 10⁻³ A

t = 2 min = 2 × 60 = 120s

Since,

Q = I × t

Q = 150 × 10⁻³ × 120

Therefore, 

Q = 18 C

Sample Question 4- For 15 minutes, a radio device uses 0.36A of electricity. Determine how much electricity travels across the circuit.

Solution:Given,

I = 0.36 A

t = 15 min = 900 seconds

Q = I × t

= 0.36 × 900

= 324 C

Sample Question 5- A current-carrying conductor may carry 6 1046 electrons over a period of 20 seconds when it is connected to an external power source. Identify the conductor's current value.

Solution: Given,

n = 6 × 10⁴⁶ electrons

t = 20s

e = 1.6 × 10⁻¹⁹ C

Since,

Q = I × t

∴I = Q/t

By the current formula,

Q = ne

∴I = ne/t

I = 6 × 10⁴⁶ × 1.6 × 10⁻¹⁹ / 20

Therefore, 

I = 4.8 × 10²⁶ A