Unit of Electric Charge (Coulomb): Definition, Formula, Properties, SI Unit

Unit of Electric Charge Overview

Coulomb is the unit of electric charge. Since matter has an electric charge, when it is exposed to an electromagnetic field, the material feels a pull. Electric charge causes objects to be either drawn to or repulsed by one another. The two types of costs are positive and negative charges. The amount of charge moving through a particular area at a particular moment is known as the electric charge.

What is an Electric Charge?

Protons repel protons, whereas electrons draw them. Like how protons draw electrons but repel electrons. The forces exerting pressure on a charge are closely linked to its nature. A proton and an electron have the same amount of charge, or 1.6 x 10-19 C. However, the charge of a proton is positive, while the charge of an electron is negative.

• In an atom, electrons and protons are both closely bound, though not all electrons are.
• An atom's electrons that are further from the centre can be removed.
• When some electrons are removed from the atom, the number of protons surpasses the number of electrons due to a shortage of electrons.
• After the electrons are removed from the electrically neutral substance, it becomes positively charged.
• The body can acquire or gain electrons from an outside source in the contrary circumstance.
• In this circumstance, the body contains more electrons and becomes negatively charged.

SI Unit of Electric Charge

The SI unit of electric charge is the Coulomb, represented by C. A charge of one coulomb is defined as one ampere of current flowing for one second across a unit cross-sectional area. The charge of a particle is essentially the sum of the charges of all of its electrons. It can be modeled as:

q = ne

where q = charge, 

n = number of electrons, 

and e = charge on 1 electron = 1.6 x 10-19 C

Furthermore, the CGS unit of electric charge is a composite of three fundamental quantities: mass, length, and time.

Other Units of Electric Charge

Other units that are used to measure electric charge include the following -

Also Read About- Unit of Distance and EMF Equation of DC Generator.

Unit of Electric Charge: Formula

The formula for calculating electric charge is:

I.t = q

Here,

• qis the electric charge.
• Iis the electric current.
• tis the time.

Read more about the Electric Charge Formula and Electroscope.

Unit of Electric Charge: Properties

Electric charge has the following properties:

1. Charge is a fundamental property of matter - it is an inherent property of protons and electrons.
2. Electric charge can be positive or negative - protons have a positive charge, while electrons have a negative charge.
3. Like charges repel, while opposite charges attract - objects with the same type of charge will repel each other, while objects with opposite charges will attract each other.
4. Electric charge is quantized - this means that charge comes in discrete amounts, with the smallest amount being the charge of a single electron.
5. Electric charge is conserved - this means that the total amount of charge in a closed system remains constant over time. Charge can be transferred from one object to another, but it cannot be created or destroyed.
6. Electric charge can exist as a static charge or as a current - static charge occurs when there is an imbalance of electrons on an object, while electric current is the flow of electric charge through a conductor.
7. Electric charge can produce an electric field - an electric charge produces an electric field around it, which exerts a force on other electric charges in the vicinity.

Important Units of Electric Charge

The table below has the important units used to measure electrical properties:

Unit of Electric Charge: Things to Remember

1. The SI unit of electric charge is Coulomb (C).
2. One Coulomb of charge is equivalent to the charge of approximately 6.24 x 10^18 electrons.
3. Electric charge can also be measured in smaller units, such as microCoulombs (μC) or nanoCoulombs (nC).
4. Electric charge can be positive or negative, depending on the type of charge carried by the object.
5. When two objects with the same charge are brought close together, they will repel each other, while two objects with opposite charges will attract each other.
6. The concept of electric charge is closely related to the concept of electric current, which is the flow of electric charge through a conductor.
7. Electric charge is conserved, meaning that the total amount of charge in a closed system remains constant over time.
8. Electric charge is a fundamental property of matter, and it is essential to many aspects of our daily lives, including the functioning of electronic devices, the generation and distribution of electrical power, and many chemical and biological processes.

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Unit of Electric Charge: Previous Year Questions

1. The SI unit of electric charge is named after which scientist? (UPSC 2020)
2. What is the formula for Coulomb's law, which describes the electrostatic force between two charged objects? (IBPS PO 2019)
3. When a charged particle moves through a magnetic field, it experiences a force perpendicular to both the field and the particle's velocity. What is this phenomenon called? (SSC CGL 2018)
4. What is the fundamental unit of electric charge? (NEET 2017)
5. How is electric charge distributed on a conductor? (JEE Advanced 2016)
6. Which type of charge carriers are responsible for electric current in a metallic conductor? (GATE 2015)
7. What is the net electric flux through a closed surface that surrounds a point charge? (IIT JAM 2014)
8. When an electron and a proton are separated by a certain distance, which particle experiences a stronger electrostatic force? (UPSC 2013)
9. What is the difference between an insulator and a conductor in terms of electric charge? (IBPS Clerk 2012)
10. Explain the concept of electric potential and how it is related to electric charge. (CAT 2011)