About NCERT Exemplar Solutions for Class 12 Physics Chapter 3 – Current Electricity
The third chapter of Class 12 physics, Current Electricity, moves from the static concepts of charges and fields into the study of charges in motion. This chapter is of immense importance as it forms the basis for understanding how electric circuits work in real life, from simple household wiring to advanced electrical networks. The NCERT Exemplar Solutions for this chapter are crafted to provide step-by-step explanations, strengthen conceptual knowledge, and help students practice a variety of application-based problems. The chapter begins with the definition of electric current as the rate of flow of charge through a conductor. The Exemplar Solutions guide students in understanding the microscopic view of current using the concept of drift velocity and mobility of charge carriers. By practicing these problems, learners gain clarity on how potential difference causes a net flow of charges and how resistance arises due to collisions within a conductor. A central theme in this chapter is Ohm’s law, which relates current, voltage, and resistance. The Exemplar problems go beyond simple definitions and challenge students to apply Ohm’s law in practical circuits. They also highlight the limitations of this law, ensuring that learners do not apply it blindly in situations where it is not valid.
The concept of electrical resistance and resistivity is explained in detail, and the Exemplar Solutions include numerical problems related to the effect of material, length, area of cross-section, and temperature on resistance. Special emphasis is given to temperature dependence, where students learn about the difference between conductors, semiconductors, and insulators. This prepares them for deeper discussions in later chapters on semiconductors and electronics. Kirchhoff’s laws form another crucial part of the chapter. The Exemplar Solutions provide step-by-step applications of Kirchhoff’s current law and voltage law to various complex circuits. Through these problems, students gain confidence in analyzing series, parallel, and mixed combinations of resistors and cells. Practice with these solutions helps them tackle network analysis, which is vital for both board exams and competitive entrance tests. The chapter also covers the concept of cells, emf, internal resistance, and the combination of cells in series and parallel. The Exemplar Solutions offer practice questions that teach how to calculate effective emf and internal resistance in different arrangements. Additionally, students encounter problems involving the potentiometer and Wheatstone bridge, two important experimental setups. These problems not only test numerical skills but also develop an understanding of experimental accuracy and measurement. In summary, the NCERT Exemplar Solutions for Current Electricity provide comprehensive practice for mastering the flow of charges in conductors and the laws governing circuits. By working through these questions, students build a strong grasp of concepts, enhance their analytical abilities, and develop the confidence to solve challenging problems in both board exams and competitive examinations like JEE and NEET.