 # Electric Charge

Electric charge is a physical property of matter that causes it to experience a force when kept in an electromagnetic field. Positive and negative are the two types of electric charges, commonly carried by charge carriers protons and electrons. When the net charge of an object equals to zero, the object is said to be neutral. The movement of electric charges are responsible for the production of one of the many types of energy known as electrical energy.

Electric Charge is defined as,

The property of subatomic particles that causes it to experience a force when placed in an electromagnetic field.

The study of electricity is divided into 3 different branches as:

• Electrostatics: It is the study of the force that acts between point charges.
• Electromagnetism: It is the study of the forces that act on the charges that are in motion.
• Electric Current: It is the study of the form of energy that is associated with the flow of charge.

## How is Electric Charge Measured?

The electric charge is measured using coulomb. 1 coulomb is the quantity of charge transferred in one second. Given by:

 Q = I.t

Where,

• Q is the electric charge
• I is the electric current
• t is the time.
 Definition The physical properties of matter which allows it to experience a special kind of force when kept under the influence of the electromagnetic field is called Electric Charge Symbol Q Formula Q = I.t SI unit Coulomb Other units Elementary charge faraday ampere-hour

## Properties of Electric Charge

The various properties of charge include the following:

• Conservation of Electric Charge
• Quantization of Electric Charge

To understand the properties of charge in detail, click on the link provided below:

### Types of electric charge

Two kinds of electric charges are there

• positive(+) charge
• negative(-) charge
• Neutral do not refer to the third type of charge, but it is a region between the positive and negative charges.

Suppose if there are identical positive and negative charges and their sum will be zero. This means they are electrically neutral.

## Columb’s Law

We might already know that like charges repel each other and unlike charges attract each other. But have you taken a minute to wonder how strong are these forces? Coloumb’s Law provides a means to calculate the strength of the force between two points. Coloumb’s Law states that,

The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

The Coloumb’s Law is given by the expression: where

• Fe is the electric force
• q1 and q2 are electric charges
• k is the Coloumb’s constant 8.988×109 N⋅m2/C2
• r is the distance of seperation

## Methods of Charging

• Induction
• Conduction
• Triboelectricity

The like charges usually repel each other and unlike charges attract each other. The SI unit for the electric charge is Coulomb and is equal to around 6.242×1018 e. The value of charge of an electron is −1.602×10-19 C. Coulomb is described as the quantity of the charge passing through a cross-section of electrical conductor which carries one ampere per second. The symbol used to denote a quantity of electricity is Q and it is directly calculated with an electrometer. When charged particles were produced by rubbing suitable materials, then we were known about the existence of charges. These facts can be demonstrated by simple examples. Take a comb and rub it on your head, place the comb near to the pieces of paper placed on the table. You will see the comb starts to attract the paper pieces.

According to the Franklin convention, the electric charge present on the comb is a positive charge and the charge present on the paper pieces is a negative electric charge. The comb which attracts the paper pieces contains positive charge and any object which repels the comb is negatively charged this is well explained through static electricity

#### Charging By Conduction #### Charging By Induction ## Practice Questions On Electric Charge

Q1: What happens

i) when two like charges are brought together?
ii) when two unlike charges are brought together?

Ans: i) When two like charges are brought together they repel.

ii) When two unlike charges are brought together they attract.

Q2: What does neutral in electric charge mean?

Ans: Neutral does not refer to the third type of charge, but it is a region between the positive and negative charges.

Hope you have learnt about electric charge its properties, formula along with terms and units. Excel your understanding by answering the practice questions and reading related links mentioned below.

Q3: Does the mass of the body get affected while charging?

Ans: Yes, the mass of the body gets affected because electons have a definite mass so the mass of the body slightly increases when it gains electrons while the mass decreases when it loses electrons.

Q4:Two identical metallic spheres of exactly equal masses are taken. One is given a positive charge q coulombs and other an equal negative charge. Are their masses after charging equal?

Ans: No. A body is positively charged due to deficit of electrons while the negative charge is due to surplus of electrons. Hence, the mass of the negatively charged sphere will be slightly more than that of the positively charged spheres.

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