Electric Charge: It is a fundamental property of matter that determines the interaction between charged particles and objects. The basic unit of electric charge is the Coulomb (C), and it is a scalar quantity that can be either positive or negative. Objects with the same electric charge will repel each other, while objects with opposite charges will attract each other. The electric charge is a result of the movement of electrons, which are negatively charged particles, within an object. The total amount of electric charge in a neutral object is zero, meaning that the number of positive charges is equal to the number of negative charges.

Unit of Electric Charge

The unit of electric charge is the Coulomb (C). It is named after the French physicist Charles-Augustin de Coulomb, who first described the inverse-square law of electrostatic attraction and repulsion. One Coulomb is defined as the amount of electric charge that passes through a point in a conductor when a current of one ampere flows for one second. In other words, one Coulomb is equal to one Ampere-second (As).

The Coulomb is a large unit, so smaller units such as microcoulombs (10^-6 C) and millicoulombs (10^-3 C) are often used in practical applications. The charge on an electron is approximately -1.6 x 10^-19 Coulombs, while the charge on a proton is approximately +1.6 x 10^-19 Coulombs. The electric charge of an object is determined by the number and type of charged particles it contains, and it can be positive, negative, or neutral, depending on the balance of positive and negative charges.

Properties of Electric Charge

The properties of electric charge include:

• Conservation: Electric charge is conserved, meaning that the total electric charge in an isolated system remains constant. This means that if a charged object is broken into smaller pieces, the total charge of the system remains the same.
• Quantization: Electric charge is quantized, meaning that it can only exist in certain discrete values. This means that electric charge can only be an integer multiple of the charge of an electron or proton.
• Additivity: Electric charge is additive, meaning that the total charge of a system is equal to the sum of the charges of its individual components.
• Sign: Electric charge can be either positive or negative, and opposite charges attract each other, while like charges repel each other.
• Transferability: Electric charge can be transferred from one object to another through contact or induction.

• Conductivity: Charged objects can conduct electricity, meaning that electric charge can flow through them. The flow of electric charge is called electric current.

Types of Electric Charge

There are two types of electric charge: 

• Positive (+) charge: Positive charge is associated with a lack of electrons, while negative charge is associated with an excess of electrons. For example, when an object gains electrons, it becomes negatively charged, and when it loses electrons, it becomes positively charged. The electric charge of an object is determined by the number of electrons it has relative to the number of protons it contains.
• Negative (-) charge: A negative charge is a type of electric charge that results from an excess of electrons in an object. Electrons are negatively charged particles, and when they accumulate on an object, they give it a net negative charge. The magnitude of a negative charge is expressed in Coulombs, and it is a scalar quantity that can be positive or negative. The charge of an electron is typically taken as the basic unit of electric charge, and it is approximately -1.6 x 10^-19 Coulombs.

How is Electric Charge Measured?

Electric charge is measured in units of Coulombs (C). A Coulomb is defined as the amount of charge transported by a steady current of one ampere in one second. The charge of a single electron is extremely small, on the order of 10^-19 Coulombs, so in most cases the charge of macroscopic objects is measured in microcoulombs (µC) or millicoulombs (mC).

There are several methods for measuring electric charge, including:

• Coulombmeter: A Coulombmeter is an instrument that directly measures the electric charge on an object by passing a known current through it and measuring the potential difference.
• Electrostatic voltmeter: An electrostatic voltmeter measures the electric potential of a charged object by comparing it to the potential of a known reference charge.
• Electrometer: An electrometer is an instrument that can measure very small charges, typically on the order of picocoulombs (pC).

• Electrophorus: An electrophorus is a device that can generate a static charge by induction. The electric charge on the plate can then be measured using an electrometer or electrostatic voltmeter.

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By Team Learning Mantras