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Chapter 13 of 14
Important Questions

Alternating Current

Bihar Board · Class 12 · Physics

Most important questions from Alternating Current for Bihar Board Class 12 Physics board exam 2026. MCQs, short answer, and long answer questions with marks.

45 questions22 flashcards5 concepts

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A graph showing the instantaneous voltage and current waveforms in a purely resistive AC circuit, demonstrating that they are in phase with each other.
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45 Questions·
multiple choicemultiple correct

Sample Questions

1multiple correct

The inductive reactance XL depends on:

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Frequency of AC, Inductance L

Inductive reactance XL = ωL = 2πfL, so it depends directly on both frequency and inductance.

2multiple choice

In a purely capacitive circuit, current:

Show answer

Leads voltage by 90°

In a capacitor, current leads voltage by π/2 or 90° because current must flow before voltage can build up across the capacitor.

3multiple choice

The impedance Z of an RLC series circuit is:

Show answer

√[R² + (XL - XC)²]

Impedance is calculated using the Pythagorean theorem from the impedance triangle, with R as one side and (XL - XC) as the other.

4multiple correct

At resonance in an RLC circuit:

Show answer

XL = XC, Current is maximum, Impedance is minimum

At resonance, XL = XC, so impedance Z = R (minimum), current is maximum, and phase angle is 0°.

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Frequently Asked Questions

What are the important topics in Alternating Current for Bihar Board Class 12 Physics?
Alternating Current covers several key topics that are frequently asked in Bihar Board Class 12 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Alternating Current — Bihar Board Class 12 Physics?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
How many important questions are there in Alternating Current?
There are 45 practice questions available for Alternating Current. These cover multiple question types including MCQs, short answer, and long answer questions.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for Bihar Board Class 12 Physics.