Glossary
Amperes (A)
The SI unit for electric current, defined as one Coulomb of charge flowing per second (1 A = 1 C/s).
Example:
A standard household light bulb might draw about 0.5 Amperes (A) of current when lit.
Charge
A fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. It's analogous to mass for gravitational interactions.
Example:
The static electricity you feel after shuffling your feet on a carpet is due to an imbalance of charge on your body.
Charge Conservation
A fundamental principle stating that the total electric charge in an isolated system never changes; it can only be transferred, not created or destroyed.
Example:
If a balloon rubs against your hair, the total charge of the balloon-hair system before and after rubbing remains the same, illustrating charge conservation.
Conservation Laws
Principles stating that certain quantities, like charge, remain constant within a closed system, even if their form or location changes.
Example:
When you transfer energy from a battery to a light bulb, the total amount of energy in the system (battery + bulb) remains constant, demonstrating the conservation laws of energy.
Coulombs (C)
The SI unit for electric charge, representing a very large quantity of elementary charges.
Example:
A typical lightning strike can transfer several Coulombs (C) of charge, highlighting how large this unit is.
Electric current
The rate of flow of electric charge through a conductor, typically measured in Amperes.
Example:
When you turn on a light switch, you complete a circuit, allowing electric current to flow and illuminate the bulb.
Elementary charge (e)
The smallest indivisible unit of electric charge, equal to the magnitude of the charge of a single proton (+1e) or electron (-1e). Its value is approximately 1.6 × 10⁻¹⁹ Coulombs.
Example:
Every electron carries exactly one elementary charge (e), making it the fundamental building block of all electric charges.
Net Charge
The algebraic sum of all individual positive and negative charges within a system. Positive and negative charges cancel each other out.
Example:
If a system has two particles with +3e and -2e, its net charge is +1e.
Neutral objects
Objects that possess equal amounts of positive and negative charge, resulting in a net charge of zero.
Example:
Most everyday objects, like a wooden table or a plastic ruler, are neutral objects because their positive and negative charges are balanced.
Static charge
Electric charge that remains accumulated in one location on an object, typically due to an imbalance of electrons.
Example:
The phenomenon of a balloon sticking to a wall after being rubbed on hair is an example of static charge.
Two types of electric charge
Electric charge exists in two forms: positive (associated with protons) and negative (associated with electrons).
Example:
Lightning occurs due to a massive separation of two types of electric charge within clouds and between clouds and the ground.