Electric Current, Resistance & Circuits Explained | Chapter 25 of University Physics
Electric Current, Resistance & Circuits Explained | Chapter 25 of University Physics Chapter 25 transitions from static charges to moving charges, introducing how electric current flows, how materials resist that flow, and how circuits distribute and use electrical energy. You’ll learn the definitions and units of current and resistance, explore Ohm’s Law, understand how batteries and generators (emf sources) behave in real circuits, and see how microscopic conduction models underpin macroscopic circuit laws. Watch the full video summary here for detailed walkthroughs of circuit analysis and experimental demonstrations. Electric Current & Current Density Electric current ( I ) is the rate of charge flow: I = dQ/dt , with SI unit ampere (A) where 1 A = 1 C/s. Current direction is defined as the flow of positive charge. Current density ( J ) quantifies how current distributes over a conductor’s cross-sectional area: J = I/A , and relates microscopically via carrie...