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Physics

Alternating Current

A Physics chapter of the NEET syllabus, and how to practise it for the computer-based exam.

Exam rules change between cycles. Confirm dates, syllabus and pattern against NTA's official site. We are not NTA.

Weightage: what the paper actually did

Alternating Current carried 3 questions in the NEET 2026 paper. One paper is a data point, not a destiny: NTA moves weight between chapters every cycle, which is why the weightage tables deserve care. The stable facts are the paper's shape: 180 questions, 720 marks, +4 right, −1 wrong.

Sample PYQs from this chapter

Real questions NTA asked from Alternating Current, with the answer and the working. Try before you peek.

Question 1 · NEET 2020

A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is π\pi/3. If instead C is removed from the circuit, the phase difference is again π\pi/3 between current and voltage. The power factor of the circuit is
  1. A.0.5
  2. B.1.0
  3. C.-1.0
  4. D.zero
Answer and explanation

Answer: B

For the RC circuit, tan(π\pi/3) = Xc/R; for the RL circuit, tan(π\pi/3) = XL/R. Hence XL = Xc in the complete series circuit, so it is at resonance and its power factor is cos 0 = 1. Chapter: Alternating Current.

Question 2 · NEET 2026

An ac circuit contains a resistance of 1 kΩ\Omega, a capacitor of 0.1 μ\muF and an inductor of 1 mH connected in series. The resonance frequency of the circuit is approximately:
  1. A.13.5 kHz
  2. B.10.1 kHz
  3. C.20.7 kHz
  4. D.15.9 kHz
Answer and explanation

Answer: D

Series resonance occurs at f0=12πLCf_0 = \dfrac{1}{2\pi\sqrt{LC}}, which is independent of the resistance. With L=1 mH=10−3 HL = 1\ \text{mH} = 10^{-3}\ \text{H} and C=0.1 μF=10−7 FC = 0.1\ \mu\text{F} = 10^{-7}\ \text{F}, f0=12π10−10=12π×10−5≈15.9 kHzf_0 = \dfrac{1}{2\pi\sqrt{10^{-10}}} = \dfrac{1}{2\pi \times 10^{-5}} \approx 15.9\ \text{kHz} (option D). The resistance value is a distractor since it does not enter the resonance formula.

How to practise Alternating Current

Chapter by chapter, against real past-paper questions, on a screen: NEET is computer based from 2027. Read the chapter once, then attempt its PYQs until your accuracy stops climbing, and let the wrong answers tell you which lines to reread. If the chapter keeps refusing to stick, that has its own guide. There is also a free NEET mini mock with answers.

Nearby Physics chapters

Questions

How many questions did Alternating Current have in NEET 2026?

Alternating Current carried 3 questions in the NEET 2026 paper. Weightage shifts between cycles, so treat it as a probability, not a promise.

Where can I practise Alternating Current PYQs for NEET?

Explore available chapter-wise NEET practice in BrainIt, free until the 2027 exam. Review explanations and track chapter accuracy to guide your revision. Sample questions from this chapter are on this page.

Is Alternating Current important for NEET 2027?

It is part of the Physics syllabus the paper draws from, and NEET 2027 is computer based, so practise it on a screen. Your own accuracy in the chapter matters more than any weightage table: a heavy chapter you already score well on needs less time than a light one you keep missing.

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