What is Electric Charge?
Atoms are the constituents of matter. Atoms are electrically neutral because the number of electrons is equal to the number of protons. Protons do carry a positive charge, whereas electrons have an equal negative charge. Photos are located in the central part of an atom, called a nucleus, along with the electrically neutral neutrons. Protons are bound with the nucleus.
An electron carries a negative charge and revolves around the nucleus in a definite orbit. The magnitude of electric charge of an electron and a proton are equal but are opposite in nature. Typically, the matter is electrically neutral because it is made up of electrically neutral particles or atoms.
Electric Charge Definition
Just like protons, the electrons are also bound in an atom, but not all electrons. The electrons which are located farther from the nucleus can be removed from the atom. When some electrons are removed from the atom, the number of protons becomes higher than the number of electrons due to a deficit in electrons. After the removal of electrons, the electrically neutral body becomes positively charged.
In the opposite case, the body can also acquire electrons from an outside source. In this case, the number of electrons in the body increases, and it becomes negatively charged.
The deficit or surplus of electrons in a body is called an electric charge.
Points to be Noted when Studying Electric Charge
The protons are positively charged
The electrons are negatively charged
The neutrons have no charge
Unit of Electric Charge
The unit of Electric Charge is Coulomb. And the value of one coulomb is the amount of charge transferred in one second. Mathematically it is represented as Q = I.t. Q is the symbol for Electric Charge.
The matter is always positively charged, negatively charged, or neutrally charged. A charge is denoted by 'q', and the SI unit of electric charge is Coulomb. The charge of a particle is basically the cumulative charges of all the electrons present in it. Mathematically it is represented as
Q = ne
where,
q = charge,
n = number of electrons, and
e = charge on 1 electron which is 1.6 × 10-19C. This is the electric charge value on an electron. The two basic natures of electric charge are
Like charges repel each other.
Unlike charges, they attract each other.
This means that the protons repel protons, while they attract electrons. Similarly, the electrons repel electrons, and they attract protons. The forces acting on a charge are directly associated with the nature of the charge. The magnitude of the charge on an electron and a proton is the same, and it is 1.6 × 10-19C. The charge on an electron is negative '-', the charge on a proton is positive '+'.
Properties of Electric Charge
Various properties of charge are given below:
Additivity of Electric Charge
Conservation of Electric Charge
Quantization of Electric Charge
In an isolated system, the electric charge is conserved, which means the net electric charge of a system remains constant. Also, the algebraic sum of the fundamental charges in any isolated system remains the same.
Electric charge is additive.
An electric charge is a conserved quantity.
Electric charge can be quantized.
Due to the presence of an electric charge, a body either attracts or repels another body based on the nature of the charge.
Friction between two different types of objects produces a positive charge on one object and a negative charge on another object. When the glass is rubbed with plastic, the glass gains excess electrons and becomes negatively charged, whereas the plastic loses electrons and becomes positively charged.
Like charges repel each other, i.e., positive charges repel positive charges and negative charges repel negative charges.
Unlike charges that attract each other, i.e., positive and negative charges attract each other.
Repulsion is the sure test to determine the nature of a charge on a body.
Types of Electric Charge
There are two kinds of electric charges:
Positive charge
Negative charge
Negative Charge
If an object has more electrons than protons, it has a negative charge. When an object gains some electrons, the number of electrons in the object becomes greater than the number of protons, and hence it becomes negatively charged.
Positive Charge
If there are more protons than electrons in an object, then the object has a positive charge. When an object loses some electrons, the number of protons in the object becomes greater than the number of electrons. Hence, the object becomes positively charged.
When the number of positive and negative charges is the same, the negative and positive charges cancel each other out and the object becomes neutral.
When a matter is placed into an electric or magnetic field it experiences a certain force, this property of matter is known as electric charge. An electric charge is linked to an electric field and the moving electric charge generates a magnetic field. The combination of electric and magnetic fields is called the electromagnetic field. Interaction between charges generates an electromagnetic force which is the foundation of Physics.
How is Electric Charge Measured?
Electric charge is measured in the unit of Coulomb. A charge is said to be 1 coulomb when a current of 1 ampere flows through a unit cross-sectional area for one second. The electric charge formula is given by:
Q = I.t
Where,
Q = electric charge
I = electric current
t = time.
Coulomb’s Law
As we already know that like charges repel each other and unlike charges attract each other. But do you know how strong these forces actually are? Coulomb’s Law provides a way to calculate the strength of the force between two points.
According to the Coulomb’s Law:
The magnitude of the electrostatic force of attraction or force of 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 the charges.
The expression of Coulomb’s Law is :
\[F_e = \frac{kq_1q_2}{r^2}\]
where Fe is the electric force, q1 and q2 are electric charges, k is the Coulomb’s constant (8.988×109 N⋅m2/C2 ) and r is the distance between two points.
FAQs on Electric Charge
1. Where can students find useful information regarding Electric charge and its properties?
Students can find everything they need on the Vedantu app or website. These study materials are created by professionals and the content is accurate and reliable. These study materials are completely free and there is no cost at all. All students just have to sign in and then they will be able to download what you want in pdf format. Students can find information about electric charge, its unit, properties and a whole lot more!
2. What is an electric charge?
When a matter is placed into an electric or magnetic field it experiences a certain force, this property of matter is known as electric charge. In other words, it is the property of subatomic particles that causes it to experience a force when placed in an electric and magnetic field. An electric charge is linked to an electric field and the moving electric charge generates a magnetic field. The combination of electric and magnetic fields is called the electromagnetic field. Interaction between charges generates an electromagnetic force which is the foundation of Physics.
3. Is Electric Charge is a scalar or a vector quantity?
Electric charge is a scalar quantity and a vector quantity has a magnitude and direction. A vector also obeys the laws of vector addition, like the triangle law of vector addition and the parallelogram law of vector addition. If a quantity satisfies all the parameters then it is considered a vector quantity. When two currents or charges meet at a point, then the resultant current of these two charges will have an algebraic sum and not the vector sum. So it is defined that an electric current is a scalar quantity, and also it has magnitude and direction.
4. What are the different kinds of Electric charges?
There are two kinds of electric charge in nature. One is a positive electric charge and the other is a negative electric charge.
Negative Charge - If an atom or molecule has more electrons than protons, it is said to have a negative charge.
Positive Charge - If an atom or molecule has more protons than electrons, it is said to have a positive charge.
When the number of positive and negative charges is the same, the negative and positive charges cancel each other out and the object becomes neutral.
5. Give some Electric Charge Examples.
During cloudy weather, lightning occurs due to the presence of a large amount of electric charge in the clouds. This suggests that the things around us also carry an electric charge stored in them.
The electrically neutral objects consist of a large number of positive and negative charges that cancel out each other, and therefore no external effects occur. A body is said to be charged, when it has a charge imbalance in its constituent particles, although it may be a short amount of charge.
When objects are charged, they exert some force on each other. For example, when a glass rod is rubbed with silk, the electrons from the glass are transferred to silk. This results in a positive charge to develop in the glass. Similarly, when silk acquires electrons, it becomes negatively charged.
6. How are Charges Produced?
When we rub a plastic comb through our hair, and after this, if we bring small pieces of paper near the comb, it starts to attract the paper. Similarly, when amber is rubbed with silk, it also starts to attract pieces of paper. These attractions and repulsions are developed in a substance because it acquires some charge.
Electric charge can be produced by rubbing one neutral object with another neutral object. Two different kinds of charges are developed on the two different objects. An object becomes positively charged while the other becomes negatively charged.
Let us consider an example. First, we have to rub a plastic rod with fur and then suspend it horizontally using a silk thread as per the diagram. Now, if we rub another plastic rod with fur and bring it near the suspended rod, we'll notice that both the rods repel each other. This is due to the presence of a similar charge.
Now, if we take a glass rod and rub it with silk and then suspend it horizontally, now we rub a plastic rod with fur and bring it near the suspended rod, we'll observe that the rods attract each other. This is due to the presence of the opposite charge. The process of rubbing develops positive and negative charges.
