Alternating Currents
Kerala Board · Class 12 · Physics
Complete topic list for Alternating Currents in Kerala Board Class 12 Physics. Key concepts, sub-topics, and what to focus on for board exams.
Topics in Alternating Currents
1. Introduction to Alternating Current and Voltage
- AC current and voltage vary sinusoidally with time, unlike DC which remains constant
- In India, AC frequency = 50 Hz, meaning current changes direction 100 times per second
- Peak values (Vm, Im) represent maximum values during oscillation
2. AC Circuit with Pure Resistor
- In pure resistive AC circuit, voltage and current are in phase (φ = 0°)
- Ohm's law applies directly: V = IR at every instant
- Power is always positive, indicating continuous energy dissipation as heat
3. Phasor Representation
- Phasors are rotating vectors representing AC quantities in vector form
- Length of phasor = peak value, projection on y-axis = instantaneous value
- Phasor diagram simplifies addition of AC quantities with different phases
4. AC Circuit with Pure Capacitor
- Current leads voltage by 90° (π/2 radians) in pure capacitive circuit
- Capacitive reactance XC = 1/ωC decreases with increasing frequency
- Average power = 0, energy alternates between electric field and source
Key Concepts
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What are the important topics in Alternating Currents for Kerala Board Class 12 Physics?
Alternating Currents covers several key topics that are frequently asked in Kerala 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 Currents — Kerala Board Class 12 Physics?
Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.
Sources & Official References
- Kerala Board of Public Examinations — keralapareekshabhavan.in
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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