Electricity Review Topics covered Characteristics of Dynamic Electricity

Electricity Review

Topics covered • Characteristics of Dynamic Electricity – Intensity – Resistance – Potential Difference – Energy – Electrical Power – Work • Circuit designs

Characteristics 1. Intensity A. Definition • The number of charges that flow past a given point in 1 second

Characteristics B. Units: – The Current Intensity is measured in Amperes (A) C. Formula: – I = q/∆t • Where I = Intensity (A) q = Charges (C) ∆t = variation in time (sec) D. In a circuit: A

Characteristics 2. Resistance A. Definition • The ability to slow down the electrons. The ability of a material to hinder the flow of the electric curent.

Characteristics B. Units: – The Resistance is measured in Ohms (Ω) C. Formula: –V=RI • Where D. In a circuit: V = Potential Difference (V) R = Resistance (Ω) I = Intensity (A)

Characteristics E. Factors affecting resistance – Nature of the substance • Better Conductor = Less resistance – Length • The shorter, the less resistance – Diameter • The fatter, the less resistance – Temperature • The colder, the less resistance

Characteristics 3. Potential Difference A. Definition • The amount of energy transferred between two points in an electrical circuit. V

Characteristics B. Units: – The Potential Difference is measured in Volts (V) C. Formula: – V = E/q • Where V = Potential Difference (V) E = Electric Energy (J) q = Charge (C) D. In a circuit: V

Characteristics 4. Electrical Power A. Definition • The amount of work an electrical device can perform per second or how much energy it can transform in a period of time.

Characteristics B. Units: – The Electrical Power is measured in Watts (W) C. Formula: – Pe = W/∆t • Where Pe = Electrical Power (W) W = Work (J) ∆t = Time Interval (sec) – Pe = V I • Where Pe = Electrical Power (W) V = Potential Difference (V) I = Intensity (A)

Characteristics C. Formula (Continued) – E = Pe∆t • Where E = Electrical Energy (J or k. Wh) Pe = Electrical Power (Pe) ∆t = Time Interval (sec or hours)

Electrical Circuits

Electrical Circuits • Types of electrical circuits A. Series circuit • Definition: – Circuit that contains only one branch or path for the electrons to follow. • Characteristics – If one element is defective, the electricity does not flow – The intensity is the same all around the circuit – The resistance adds up

Electrical Circuits B. Parallel circuit • Definition – Circuit that contains at least one branch or paths for the electrons to follow. • Characteristics – If an element is defective, the elements on that particular branch will stop working only – Resistance is shared (so resistance is lower) – Current intensity adds up

Electrical oddities • A switch must be closed in order to allow the energy to flow • A light will only light up when the electrons complete a full circuit (one side of the power source to another)