NCERT Solutions for Class 12 Physics, Chapter 3 - Current Electricity

In this chapter, you’ll study current electricity and a few fundamental laws related to steady electric current. Current electricity is nothing but the electricity in motion, with either negativity charged electrons or positivity charged ions.  It can either be a thunderbolt or a spark that happens on the switchboard when you switch on the light. In this chapter, you’ll learn what an electric current is, application of electric current in conductors, the famous Ohm’s Law, significance as well as drawbacks of Ohm’s Law, what is resistivity, resistivity of different materials, electrical energy and power, series as well as parallel resistors, the importance of Kirchhoff’s Rules and what is Wheatstone Bridge all about. Finally, you’ll also study what is Meter Bridge and potentiometer.

Thus, an in-depth study of Class 12 Physics NCERT Solutions Chapter 3 will give you a good understanding of current electricity.

Let’s take a look at topics and sub-topics of Class 12 Physics Chapter 3 – Current Electricity

3.1 Introduction

3.2 Electric Current

3.3 Electric Currents in Conductors

3.4 Ohm’s law

3.5 Drift of Electrons and the Origin of Resistivity

3.5.1 Mobility

3.6 Limitations of Ohm’s Law

3.7 Resistivity of Various Materials

3.8 Temperature Dependence of Resistivity

3.9 Electrical Energy, Power

3.10 Combination of Resistors – Series and Parallel

3.11 Cells, emf, Internal Resistance

3.12 Cells in Series and in Parallel

3.13 Kirchhoff’s Rules

3.14 Wheatstone Bridge

3.15 Meter Bridge

3.16 Potentiometer

In Class 12 Physics Chapter 3, you will learn –

Section 3.2 – In this section, you will study about electric current, some features of electric current and what do you mean by an ampere.

Section 3.3 – In this section, you’ll learn about Electric Currents in Conductors. You’ll also study what is ionosphere and what happens when no electric field is present.

Section 3.4 – In this section, you’ll acquire knowledge about the basic law regarding the flow of currents proposed by G.S. Ohm in 1828. You’ll also learn what is the resistance of the conductor, what is the potential difference across the ends of the combination, what is current density and conductivity.

Section 3.5 – In this section, you’ll learn about the drift of electrons and the origin of resistivity, a schematic picture of an electron moving from a point A to another point B through repeated collisions and what do you mean by the current in a metallic conductor.

Section 3.6 – In this section, you will study about limitations of Ohm’s Law, the characteristic curve of a diode and variation of current versus voltage for GaAs.

Section 3.7 – In this section, you will learn about the resistivities of various common materials, classification of materials depending on their resistivities, wire-bound resistors and carbon resistors, and finally the advantages of carbon resistors.

Section 3.8 – In this section, you’ll learn that the resistivity of a material is dependent on the temperature, what is temperature coefficient of resistivity and some graphs showing resistivity in detail.

Section 3.9 – In this section, you will study about electrical energy and power along with related equations and diagrams. You’ll also be able to answer questions like – where does power come from and what are the uses of transformers.

Section 3.10 – In this section, you’ll acquire knowledge about the combination of resistors such as series and parallel. You’ll also come across the graphical representation showing A series combination of two resistors R1 and R2 and A series combination of three resistors R1, R2 and R3.

Section 3.11 – In this section, you’ll learn about cells, emf and internal resistance.  You’ll study what is an electrolytic cell, the electromotive force (emf) of the cell, what is internal resistance, the charges in clouds, and more.

Section 3.12 – In this section, you’ll study cells in series and cells in parallel. You’ll also learn about the interesting contributions made by Gustav Robert Kirchhoff (1824 – 1887) German physicist who was a professor at Heidelberg and at Berlin.

Section 3.13 – In this section, you will study two rules, called Kirchhoff’s Rules, which are extremely crucial for the analysis of electric circuits such as the junction rule and the loop rule.

Section 3.14 – In this section, you will learn what you mean by Wheatstone Bridge, how many resistors the Wheatstone Bridge has, what a balanced bridge is and what is a balanced condition.

Section 3.15 – In this section, you will come across the term – ‘Meter Bridge’. You’ll also study the diagrammatical representation of the meter bridge.

Section 3.16 – In this section, you will learn what do you mean by a potentiometer, its uses, advantages and finally how a potentiometer works.

In this chapter, you are provided with several examples with their solutions for a clear understanding of Current Electricity. To know more about NCERT Solutions for Class 12 Physics Chapter 3, you should explore the exercises mentioned in this chapter. You can also download the NCERT Solutions for Class 12 Physics Chapter 3 PDF, solved by our science experts.