ELECTRICITY & ELECTRICAL CHARGES

WHAT IS ELECTRICITY? Electricity describes all the phenomena caused by positive and negative charges.

WHAT IS ELECTRICITY?  

Coulomb The coulomb is the unit of measurement for electrical charge. One coulomb is equal to the charge of 6.25 x 1018 electrons or protons. Symbol: C

Practice Problem During a storm, impressive bolts of lightning form jagged lines across the sky. The lightning is caused by a brief but powerful electrical discharge. If the electrical discharge of a lightning bolt is equal to 20 C, how many electrons were involved in the neutralization process? 20 C = ? electrons 1 C = 6.25  1018 electrons 20 C is equal to a charge of 1.25  1020 electrons

Electrical Forces Charging an object consists in creating an imbalance in the electrical charge of that object. The law of conservation of charge states that electrical charges can be neither created nor destroyed; they can only be transferred from one body to another.

Electrical Charges Electrical charges of like signs repel each other. Like repels like.

Electrical Charges Electrical charges of opposite signs attract each other. Opposites attract.

Conductors & Inductors A conductor is a substance that permits the free flow of electrical charges. An insulator is a substance that impedes the free flow of electrical charges.

Factors that Affect Current There are four factors that affect current flow: Nature of substance Length Thickness Temperature Ideal conductor: Copper, Short, Large Diameter, Cold

Electric Circuit An electric circuit is a network in which electrical charges can flow continuously in a loop.

Electric Circuit All circuits contain at least three components: Power supply Wires to carry the charges to and from the power supply One or more elements that use electrical energy (such as a light bulb or resistor)

Series Circuit A series circuit is a circuit in which the elements are connected end to end.

Series Circuit In a series circuit, the current intensity through each of the components is the same. It = I1 = I2 = I3 = … The potential difference across the circuit is the sum of voltages across each component. Vt = V1 + V2 + V3 + … The total resistance across the circuit is the sum of resistances across each component. Rt = R1 + R2 + R3 + …

Measuring Current Intensity in a Series Circuit

Measuring Potential Difference in a Series Circuit

Parallel Circuit A parallel circuit is a circuit that contains at least one branch.

Parallel Circuit In a parallel circuit, the potential difference across each of the components is the same. Vt = V1 = V2 = V3 = … The total current intensity is the sum of the currents through each component. It = I1 + I2 + I3 + …