Understanding Static Electricity and Electric Current

Static electricity:

• There are electrostatic forces between particles or objects with a positive or a negative charge.
• Charge is due to the surplus or defect of electrons.
• Like charges repel each other while opposite charges attract each other.
• Electric charge is measured in coulomb (C) and has the symbol Q.
• When there is an imbalance of positive and negative charge, we get a force between the charges according to Coulomb's law.

Electric current:

• Electric current is a flow of electrons or other charges through a material.
• Conductor: Electrons can move easily through the conductor.
• Insulator: It is very difficult for electrons to move through the material. The electrons are not free to move and form bonds.

Electrical Magnitudes:

• Potential difference is the energy (E) needed to move one unit of charge (Q) from one point to another. The unit is volts (V).
• Current intensity is the amount of charge (Q) that passes through a conductor at a certain time. The unit is Ampere (A).
• Electrical resistance is a measure of the opposition to the flow of current. It depends on the material's resistivity. The unit is Ohm (Ω).
• Ohm's law states the relationship between voltage (V), current (I), and resistance (R) in a circuit: V = I * R, I = V / R, R = V / I.