Physics · Class 12 · Chapter 3

Current Electricity

12 lessons126 min10 simulations9 practice questions

This chapter deals with charges in steady motion through conductors. It defines current and current density, states Ohm's law, explains resistance at the microscopic level through the drift of free electrons, looks at how resistivity changes with material and temperature, and then treats electrical power, cells with internal resistance, combinations of cells, Kirchhoff's rules and the Wheatstone bridge.

Also called: Ohm's law · Kirchhoff's laws · Wheatstone bridge · potentiometer

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Lessons

12 lessons · 126 min

01Electric currentNCERT § "Electric Current"7 min 02Electric currents in conductors and Ohm's lawNCERT § "Ohm's Law"11 min1 sim 03Electron drift and where resistivity comes fromNCERT § "Drift of Electrons and the Origin of Resistivity"11 min1 sim 04MobilityNCERT § "Mobility"6 min 05Limitations of Ohm's lawNCERT § "Limitations of Ohm's Law"7 min 06Resistivity of materials and its temperature dependenceNCERT § "Resistivity of Various Materials" and § "Temperature Dependence of Resistivity"9 min1 sim 07Electrical energy and powerNCERT § "Electrical Energy, Power"10 min1 sim 08Cells, emf and internal resistanceNCERT § "Cells, emf, Internal Resistance"10 min1 sim 09Cells in series and in parallelNCERT § "Cells in Series and in Parallel"10 min1 sim 10Kirchhoff's rulesNCERT § "Kirchhoff's Rules"14 min2 sims 11Wheatstone bridgeNCERT § "Wheatstone Bridge"13 min2 sims 12Chapter reviewMust-know facts, traps and formulas18 min

Simulations

10 in this chapter

Stretch a wire and watch its resistanceIn: Electric currents in conductors and Ohm's law How fast do electrons really move in a wire?In: Electron drift and where resistivity comes from Resistivity as temperature changesIn: Resistivity of materials and its temperature dependence Two bulbs on the mainsIn: Electrical energy and power Why the terminal voltage is less than the emfIn: Cells, emf and internal resistance Two cells: in series, in parallel, and one reversedIn: Cells in series and in parallel How current divides between branchesIn: Kirchhoff's rules Walking round a loop with KirchhoffIn: Kirchhoff's rules Balance a Wheatstone bridgeIn: Wheatstone bridge Metre bridge: find the unknown resistanceIn: Wheatstone bridge