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Ac Through an Inductor and Capacitor
An ideal inductor and capacitor oppose alternating current through frequency-dependent reactance and create phase differences between voltage and current.
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Ac Through an Inductor and Capacitor
What is it?
An ideal inductor and capacitor oppose alternating current through frequency-dependent reactance and create phase differences between voltage and current.
In simple words
- Inductive reactance rises with frequency; capacitive reactance falls with frequency.
Recommended for Class 12
Full school-level explanation
An ideal inductor and capacitor oppose alternating current through frequency-dependent reactance and create phase differences between voltage and current.
Pure Inductor
Inductive reactance: XL=ωL=2πfL RMS current: I=VXL In a pure inductor: current lags voltage by 90°. Increasing frequency increases `X_L`.
Pure Capacitor
Capacitive reactance: XC=1ωC=12πfC RMS current: I=VXC In a pure capacitor: current leads voltage by 90°. Increasing frequency decreases `X_C`.
Memory Rule
L → current Lags C → current Comes first
Formula / Key Relation
XL=ωL XC=1ωC Inductor: I lags V by 90° Capacitor: I leads V by 90°
Remember
- XL=ωL=2πfL
- I=VXL
- current lags voltage by 90°
- XC=1ωC=12πfC
- I=VXC
- current leads voltage by 90°
- L → current Lags
- C → current Comes first
Deeper understanding
Go deeper on Ac Through an Inductor and Capacitor: connect the definition to reasons, relationships, exceptions, and exam wording.
Common mistakes
Exam focus
Inductor
Exam focus
Quick revision
- XL=ωL=2πfL
- I=VXL
- current lags voltage by 90°
- XC=1ωC=12πfC
- Pure Inductor: Inductive reactance: XL=ωL=2πfL RMS current: I=VXL In a pure inductor: **current lag
- Pure Capacitor: Capacitive reactance: XC=1ωC=12πfC RMS current: I=VXC In a pure capacitor: **c
For long answers on Ac Through an Inductor and Capacitor: define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- XL=ωL=2πfL
- I=VXL
- current lags voltage by 90°
- XC=1ωC=12πfC
Important formulas
- XL=ωL=2πfL
- I=VXL
- current lags voltage by 90°
Common exam traps
- Do not interchange `X_L` and `X_C`.
- Do not say both reactances increase with frequency.
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Do not interchange `X_L` and `X_C`.
- Mistake
Do not say both reactances increase with frequency.
- Mistake
Do not interchange `X_L` and `X_C`.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
XL=ωL=2πfL
I=VXL
current lags voltage by 90°
XC=1ωC=12πfC
An ideal inductor and capacitor oppose alternating current through frequency-dependent reactance and create phase differences between voltage and curren
XL=ωL=2πfL
- Definition
- An ideal inductor and capacitor oppose alternating current through frequency-dependent reactance and create phase differences between voltage and curren
- Formula
- XL=ωL=2πfL
- Critical warning
- Do not interchange `X_L` and `X_C`.
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Exam Practice
Define
Q1. Define Ac Through an Inductor and Capacitor.
Explain
Q2. Explain: Pure Inductor.
Example
Q3. Give one clear example of Ac Through an Inductor and Capacitor and say why it fits.
Mistake
Q4. State one common mistake students make about Ac Through an Inductor and Capacitor.
Exam note
Q5. Write a short exam note on Ac Through an Inductor and Capacitor: definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.