NCERT Exemplar Solutions for Class 12 Physics Chapter 7

About NCERT Exemplar Solutions for Class 12 Physics Chapter 7 – Alternating Current

The seventh chapter of Class 12 Physics, Alternating Current, focuses on one of the most important branches of electrical science that finds extensive application in everyday life. Unlike direct current, which flows in one direction, alternating current changes its direction and magnitude periodically. This chapter explains the principles, mathematical treatment, and applications of alternating current in detail. The physics NCERT Exemplar Solutions for this chapter provide students with systematic guidance to solve a variety of problems, thereby enhancing both conceptual clarity and numerical proficiency. The chapter begins with a discussion on the generation of alternating current. Students learn how an alternating emf is produced by rotating a coil in a magnetic field. The Exemplar Solutions present problems that help learners calculate instantaneous values of current and voltage, frequency, and angular frequency, strengthening their ability to connect mathematical expressions with physical phenomena. One of the central topics is the study of AC circuits containing resistors, inductors, and capacitors. The NCERT Exemplar Solutions cover questions on purely resistive, inductive, and capacitive circuits as well as combinations like series LCR circuits. These solutions show how to calculate current, voltage, phase difference, and impedance, helping students understand how energy is stored and transferred in such systems. The concept of reactance and its role in opposing current flow is also thoroughly practiced through these problems.

A major focus of this chapter is resonance in AC circuits. The Exemplar Solutions provide step-by-step explanations on how to determine resonant frequency, impedance, and power in a resonant LCR circuit. These problems help students appreciate why resonance is important in tuning devices like radios and in minimizing energy losses in electrical systems. Another significant area is the analysis of power in AC circuits. The Exemplar Solutions include numerical and conceptual questions on power factor, average power, and the role of phase difference between voltage and current. Students also learn the importance of power factor correction in efficient energy transmission, a concept vital for practical electrical engineering. The chapter also introduces transformers, one of the most important applications of alternating current. Problems in the Exemplar guide students to calculate voltage transformation ratio, efficiency, and losses, linking theory to real-world power distribution systems. In conclusion, the NCERT Exemplar Solutions for Alternating Current provide comprehensive support for mastering both theoretical concepts and mathematical applications. By solving these problems, students strengthen their understanding of alternating current, enhance their analytical abilities, and gain confidence for both board examinations and competitive tests like JEE and NEET. This chapter not only boosts academic preparation but also offers insights into the electrical systems that power our daily lives.