Electric Charge
Fundamental property of matter responsible for electric phenomena, existing in two types: positive and negative.
What is Electric Charge?
An intrinsic property of matter associated with the exchange of electrons or protons, responsible for electromagnetic interactions.
Key formula / rule: Quantization of Charge
Key points
- Define electric charge and its properties.
- Identify the two types of electric charge.
- State the SI unit of charge and the value of the elementary charge.
- Explain the principles of conservation and quantization of charge.
Common exam trap
Confusing charge with mass.
Definitions
- Term
Electric Charge
- Meaning
An intrinsic property of matter associated with the exchange of electrons or protons, responsible for electromagnetic interactions.
- Term
Coulomb (C)
- Meaning
The SI unit of electric charge.
- Term
Elementary Charge (e)
- Meaning
The smallest unit of electric charge that can be isolated, equal to the magnitude of the charge of an electron or proton.
- Term
Quantization of Charge
- Meaning
The principle that electric charge exists only in discrete multiples of the elementary charge 'e'.
- Term
Conservation of Charge
- Meaning
The principle that the total electric charge in an isolated system remains constant over time.
Learning objectives
Define electric charge and its properties.
Identify the two types of electric charge.
State the SI unit of charge and the value of the elementary charge.
Explain the principles of conservation and quantization of charge.
Describe methods of charging objects.
Formulae
- Name
Quantization of Charge
- Note
Where Q is the total charge, n is an integer (positive, negative, or zero), and e is the elementary charge.
- Expression
Q = n * e
- Name
Elementary Charge
- Note
Magnitude of charge on an electron or proton.
- Expression
e = 1.602 x 10-19 C
Prerequisites
Basic understanding of matter and atoms.
Concept of elementary particles (electrons, protons).
Common mistakes
Confusing charge with mass.
Assuming charge can be created or destroyed.
Not understanding the quantized nature of charge.
Incorrectly applying attraction/repulsion rules.
Forgetting the sign of the elementary charge.
Keywords
Electric Charge
Positive Charge
Negative Charge
Coulomb
Elementary Charge
Quantization
Conservation
Electrostatics
Electron
Proton
Practice preview
What are the two types of electric charge?…
easy
An object is said to be positively charged if it:…
medium
Which of the following statements about electric charge is INCORRECT?…
medium