NCERT Class 12 Physics Chapter 7 Alternating Current Solutions - Download Free PDF

With detailed NCERT Solutions for Alternating Current Class 12, students can master phasor diagrams, resonance, power factor, and numerical problems easily.

How will our solutions help you with this chapter?

The NCERT Class 12 Physics Chapter 7 Solutions are designed to give conceptual clarity, numerical accuracy, and exam-oriented preparation. The solution PDF gives a complete step-by-step explanation of the NCERT questions, in-text questions, and additional problems.

• Clear and accurate derivations of the formula, along with diagrams, help you score well in theory questions.
• Numerical questions include all intermediate calculations, unit conversions, and the final answer for your practice.
• Topics like wattless current and Q-factor, which create confusion among students, are explained in simple language.

Overall, the solutions help you to boost your confidence, improve speed and accuracy, and ensure you score good marks in NCERT Physics Chapter 7.

How to Study Physics Class 12 Chapter 7 Alternating Current Effectively

For this chapter, students should focus more on conceptual clarity. Students can start with NCERT examples, practice phasor diagrams, and cover theoretical questions, then jump to numericals.

• The NCERT Class 12 Physics Chapter 7 solution PDF covers everything in order, starting with questions from NCERT examples, exercise questions, NCERT exemplar questions, and important questions from other reference books.
• Students should try to solve questions by themselves first, then take reference from the solution PDF for a detailed understanding of the concept.
• The solution PDF is designed in such a way that students can use it for first reading to exam day revision.

Time required for Physics Class 12 Chapter 7:Alternating Current

The NCERT Class 12 Physics Chapter 7 is considered moderate in difficulty and shorter than other chapters of Class 12 Physics. On average, around 6 to 8 hours are needed to complete this chapter properly, including theory, numerical, and practice.

With proper planning and considering important topics, this chapter can be completed in 4-5 hours by keeping the focus clear.

• For revising after completion of this chapter, give 1-2 hours on formula, diagrams, and confusing terms(Peak value,rms value, etc.)
• If studied with Electro Magnetic Induction, this unit can be covered in 10-12 hours effectively.

Regular self-evaluation using the attached NCERT Solutions Class 12 Physics Chapter 7 helps reduce overall study time by clearing doubts quickly.

Important Topics in Alternating Current Class 12 NCERT

It is very important to understand which topics are frequently asked in the exams to plan your preparation accordingly. In Alternating Current, topics like AC Phasors, Voltage Circuit, LCR Circuit, Oscillations, and Transformers are asked repeatedly in the Boards, as well as in other competitive exams.

NCERT Physics Class 12 Chapter 7 Alternating Current: Previous Year Paper Analysis

Understanding the previous year's paper analysis helps you understand the exam pattern better and prepare for the most repeated concepts accordingly.

• The relationship between RMS, Peak, and Average value is asked almost every year in CBSE Board Exams in the form of MCQ or short-answer type.
• Questions based on transformers are repeated in the short-answer or long-answer types, which makes it one of the most important topics for boards.
• Understanding the LCR circuit and the Phasor diagram (not asked to draw separately) helps you analyse the case study problem well and answer it with accuracy.

Source:

• CBSE Class 12 Physics Set 1 Question Paper 2026
• CBSE Class 12 Physics Set 2 Question Paper 2026
• CBSE Class 12 Physics Set 3 Question Paper 2026

Weightage of Alternating Current in JEE Main, NEET & CUET

This chapter carries moderate but consistent weightage in Boards, JEE, NEET, and CUET. The JEE main is more focused on numerical questions from this unit, while NEET and CUET often ask theoretical questions or application-based questions.

• Students can expect around 1-2 questions from this chapter in every shift of JEE Main, focusing mainly on Power factor and Phasor Diagrams.
• For NEET, students can expect around 2 questions and 3-4 marks in CUET, focusing mainly on resonance, impedance, LCR circuits, and transformers.

Step-by-Step Guide to Solve Numerical Problems in Alternating Current

Students can score full marks in Numerical problems solved with the correct approach. In the NCERT class 12 Physics chapter 7, most of the numerical problems revolve around Peak value, RMS value, Impedance, resonance, power, and transformers.

Students can refer to our NCERT Class 12 Physics Chapter 7 solutions for a complete breakdown of numerical questions.

Here are some steps that students should follow while solving numerical problems:

• Read the question carefully and note down all the given values (V, I, Z, etc.)
• Identify the circuit type from the given values and draw its phasor diagram.
• Try to write down all related formulas in rough to identify which fits well for the required value.
• Verify the calculations before finalising your answer.
• Always mention units at each and every step.
• Write the final answer along with the unit in the box.

Students can follow the above steps for securing good marks in numerical problems.

Common Mistakes Students Make in Chapter 7 Alternating Current

Students lose a lot of their marks due to conceptual confusion and calculation mistakes. Practicing while keeping the common mistakes in mind will help you escape those during the exam.

Here are some common mistakes students usually make:

• Confusion between peak and rms value while calculating current and voltage.
• Forgetting to draw a phasor diagram or incorrect phasor diagram.
• Calculating average power without considering the power factor.
• Interchanging the turn ratio values of voltage and current in transformer questions.
• Ignoring units during the final answer.
• Depending on rote learning rather than understanding derivations, graphs, and concepts.