Skip to main content
Super TutorResources
Chapter 14 of 28
SyllabusNotesTopicsQuestionsPlanFormulas
Revision Notes

Alternating Current — Revision Notes

IISER Aptitude Test · Physics

Free Alternating Current revision notes for IISER Aptitude Test Physics 2026 — key concepts, formulas, and definitions for quick revision.

Interactive on Super Tutor

Studying Alternating Current? Get the full chapter — free.

Practice questions, revision notes, formula sheet and AI doubt-solver — built for IISER Aptitude Test Physics.

Try Super Tutor — Free
A comparison of Alternating Current (AC) and Direct Current (DC) waveforms, showing AC as a sinusoidal wave changing direction and magnitude, and DC as a constant, unidirectional line.
Super Tutor

Super Tutor has 30+ illustrations like this for Alternating Current alone — flashcards, concept maps, and step-by-step visuals.

See them all

Revision Notes — Alternating Current

Key concepts, formulas, and definitions from Alternating Current for IISER Aptitude Test Physics preparation.

Key Topics to Revise

1

Fundamentals of Alternating Current

  • AC current magnitude changes continuously with time and direction reverses periodically
  • AC is preferred over DC because it can be easily converted using transformers
  • Current and voltage can be represented as sine or cosine functions
2

AC Voltage Applied to Pure Components

  • Pure Resistor: Current and voltage are in phase (φ = 0°)
  • Pure Inductor: Current lags voltage by 90° (φ = -90°)
  • Pure Capacitor: Current leads voltage by 90° (φ = +90°)
3

Series LCR Circuit and Impedance

  • Total opposition to AC current is called impedance (Z)
  • Impedance combines resistance and net reactance vectorially
  • Phase angle depends on relative values of X_L and X_C
4

Resonance in AC Circuits

  • Resonance occurs when X_L = X_C in LCR circuit
  • At resonance, impedance is minimum and equals resistance R
  • Current is maximum at resonant frequency

Get complete revision notes with diagrams and examples — continue in Super Tutor

Key Concepts

AC voltage/current varies as V =In a purely resistive circuitIn a purely inductive circuitIn a purely capacitive circuitIn series LCR circuits

Frequently Asked Questions

What topics are covered in Alternating Current for IISER Aptitude Test?
Alternating Current is an important chapter in IISER Aptitude Test Physics. It covers key concepts and formulas that are frequently tested in the exam. Key topics include: Fundamentals of Alternating Current, AC Voltage Applied to Pure Components, Series LCR Circuit and Impedance, Resonance in AC Circuits.
How important is Alternating Current for IISER Aptitude Test?
Alternating Current is a frequently tested chapter in IISER Aptitude Test Physics. Questions from this chapter appear regularly in previous year papers. There are 242 practice questions available for this chapter.
How to prepare Alternating Current for IISER Aptitude Test?
Start by understanding the core concepts, then solve practice questions. Focus on formulas and their applications. Use revision notes for quick review before the exam.

More resources for Alternating Current

All 28 chapters — IISER Aptitude Test Physics Revision Notes

For IISER Aptitude Test aspirants

Get the full Alternating Current chapter — for free.

Practice questions, revision notes, formula sheet and AI doubt-solver for IISER Aptitude Test Physics.

Try Super Tutor Free
Try the full chapter — Free