Physics
Current Electricity
विद्युत धारा
Chapter 3, Current Electricity, introduces Class 12 Physics students to the movement of electric charge through conductors and the factors that control current. It explains drift velocity, potential difference, Ohm’s law, resistance, resistivity, and the temperature dependence of resistance. Students also study series and parallel combinations, cells and internal resistance, Kirchhoff’s laws, and practical methods such as the Wheatstone bridge, meter bridge, and potentiometer, while developing skills to interpret circuits and solve numerical problems.
1Drift Velocity and Mobility
अपवाह वेग और गतिशीलता
In Class 12 Physics, Chapter 3: Current Electricity, this topic explains how charge carriers move through a conductor when an electric field is applied. Students learn that drift velocity is the average directed speed acquired by electrons, despite their random thermal motion, and understand its relation to current, charge density, and the number of carriers. The topic also introduces mobility, defined as drift velocity per unit electric field, and connects it with relaxation time and electrical conductivity.
0 questionsOhm's Law, Electrical Resistance, and Resistivity
ओम का नियम, विद्युत प्रतिरोध और प्रतिरोधकता
In Class 12 Physics, this topic from Chapter 3: Current Electricity explains how potential difference, current, and resistance are related through Ohm’s law, V = IR. Students examine the meaning of resistance, interpret V–I graphs, and learn how resistance depends on a conductor’s length, cross-sectional area, material, and temperature. The topic also introduces resistivity as an intrinsic property of a material, its SI unit, and its role in comparing conductors and insulators. Examples and numerical problems help connect these ideas with practical circuits.
0 questionsTemperature Dependence of Resistivity
तापमान पर प्रतिरोधकता की निर्भरता
In Class 12 Physics, this topic from Chapter 3: Current Electricity explains how a material’s resistivity changes when its temperature changes. Students study the approximately linear relation for metals, ρ = ρ₀[1 + α(T − T₀)], and interpret the temperature coefficient of resistivity. They also compare the behaviour of metals, alloys, semiconductors, and insulators, connect resistivity with resistance and conductivity, and understand practical uses such as resistance thermometers and temperature-sensitive circuits.
0 questionsElectrical Energy and Power
विद्युत ऊर्जा और शक्ति
Electrical Energy and Power is a Class 12 Physics topic within Chapter 3, Current Electricity. It explains how electric charge transfers energy through a circuit and how quickly that energy is delivered or converted, introducing the relations P = VI, P = I²R, and P = V²/R. Students connect voltage, current, and resistance with power dissipation in resistors, calculate electrical work and energy, and interpret units such as watt, joule, and kilowatt-hour. The topic also supports practical understanding of electricity use in circuits and appliances.
0 questionsCells, EMF, Internal Resistance
विद्युत सेल, ईएमएफ और आंतरिक प्रतिरोध
In Class 12 Physics, this topic explains how an electric cell converts chemical energy into electrical energy and how its electromotive force (EMF) differs from terminal potential difference. Students study internal resistance, the relationship between current, EMF, terminal voltage, and energy loss, and learn to analyse cells connected in series and parallel. It also builds skills for solving circuit problems and understanding open-circuit and loaded-cell conditions in Chapter 3, Current Electricity.
0 questionsCells in Series and Parallel
सेलों का श्रेणीक्रम और समानांतर संयोजन
In this Class 12 Physics topic from Chapter 3, Current Electricity, students learn how cells are combined in series and parallel to supply electrical energy. They study the effective emf and internal resistance of each arrangement, derive the resulting current and terminal voltage, and understand how the combination affects circuit performance. The topic also helps students compare series and parallel connections and apply these ideas to practical circuit problems involving batteries and external resistance.
0 questionsKirchhoff's Rules
किर्चहॉफ के नियम
Kirchhoff’s Rules is a Class 12 Physics topic in Chapter 3: Current Electricity. Students learn how the junction rule, based on conservation of charge, and the loop rule, based on conservation of energy, help analyse circuits with multiple branches, cells and resistors. The topic explains how to assign current directions and voltage signs, form simultaneous equations, and calculate unknown currents, potential differences and resistances in complex electrical networks.
0 questionsWheatstone Bridge
व्हीटस्टोन सेतु
In Class 12 Physics, this topic from Chapter 3: Current Electricity explains how a Wheatstone Bridge compares electrical resistances accurately. Students study its four-arm arrangement, the role of the galvanometer as a null detector, and the balance condition under which no current flows through the galvanometer. They apply the relation between the four resistances to determine an unknown resistance and understand how the principle supports practical measurement methods such as the meter bridge.
0 questionsElectric Current and Flow of Electric Charges in a Metallic Conductor
धात्विक चालक में विद्युत धारा और विद्युत आवेश का प्रवाह
In Class 12 Physics, Chapter 3: Current Electricity, this topic explains how electric charge moves through a metallic conductor and how that motion produces electric current. Students connect the conventional direction of current with the actual drift of free electrons, understand the role of an electric field, and relate charge flow to current, drift speed, and charge density. The topic builds a microscopic understanding of current that supports the study of resistance, Ohm’s law, and electrical circuits.
3 questions