Alternating Current — Class 12 Physics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 12 Physics chapter "Alternating Current" — 6 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 12 Physics chapter "Alternating Current" — 6 important questions with detailed answers for CBSE board exam…
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Key Questions Covered:
- Define AC current and voltage. Explain peak value, RMS value, and average value.
- Explain AC circuit with pure resistance. Draw phasor diagram and power equation.
- Explain AC circuit with pure inductance (L). Draw impedance and phasor diagram.
- + 3 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Define AC current and voltage. Explain peak value, RMS va… | ✓ Solved |
| Explain AC circuit with pure resistance. Draw phasor diag… | ✓ Solved |
| Explain AC circuit with pure inductance (L). Draw impedan… | ✓ Solved |
Showing 3 of 6 questions
Q1: Define AC current and voltage. Explain peak value, RMS value, and average value.
AC (Alternating Current): Electric current that reverses direction periodically with time.
I = I₀ sin(ωt + φ) or I = I₀ cos(ωt + φ)
where I₀ = peak (maximum) current
ω = angular frequency (rad/s)
t = time
φ = phase constant
AC Voltage: V = V₀ sin(ωt + φ)
where V₀ = peak voltage
Three Important ...
Q2: Explain AC circuit with pure resistance. Draw phasor diagram and power equation.
AC Circuit with Pure Resistance (R):
Circuit: AC source connected to resistor R only (no L or C)
Voltage applied: V = V₀ sin(ωt)
Current through resistor (Ohm's law):
I = V/R = (V₀/R) sin(ωt) = I₀ sin(ωt)
where I₀ = V₀/R (peak current)
Key Observations:
1. Current and voltage in phase (φ = 0°)
...
Q3: Explain AC circuit with pure inductance (L). Draw impedance and phasor diagram.
AC Circuit with Pure Inductance (L):
Circuit: AC source connected to pure inductor only (no R or C)
Voltage applied: V = V₀ sin(ωt)
Induced emf in inductor:
ε = -L(dI/dt) = -V (opposes applied voltage)
From Faraday's law:
V = L(dI/dt)
V₀ sin(ωt) = L(dI/dt)
Integrating:
I = -(V₀/ωL) cos(ωt) = (V...
Showing 3 of 6 questions. Visit the full page for complete solutions.