AC Circuits, Reactance & Power Factor MCQs
AC Circuits, Reactance & Power Factor – MCQs
Class: 12 | Subject: Physics |
Section: Electromagnetic Induction & Alternating Current |
Topic: AC Circuits, Reactance & Power Factor
Based on: NCERT Syllabus | CBSE Board Examination Standard
Based on: NCERT Syllabus | CBSE Board Examination Standard
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination preparation.
1. Reactance is opposition offered by:
Answer: B
Reactance arises in AC due to L and C.
Reactance arises in AC due to L and C.
2. Inductive reactance XL =
Answer: A
Opposition by inductor.
Opposition by inductor.
3. Capacitive reactance XC =
Answer: B
Opposition by capacitor.
Opposition by capacitor.
4. Reactance unit:
Answer: B
Same as resistance.
Same as resistance.
5. Impedance is vector sum of:
Answer: C
Total opposition in AC.
Total opposition in AC.
6. Power factor =
Answer: B
Phase cosine.
Phase cosine.
7. Power factor unit:
Answer: C
It is a ratio.
It is a ratio.
8. True power =
Answer: B
Actual useful power.
Actual useful power.
9. Reactive power unit:
Answer: B
Volt‑Ampere Reactive.
Volt‑Ampere Reactive.
10. Apparent power =
Answer: A
Total supplied power.
Total supplied power.
11. Power factor improves by:
Answer: A
Neutralizes inductive lag.
Neutralizes inductive lag.
12. Pure resistor PF =
Answer: C
No phase difference.
No phase difference.
13. Pure inductor PF =
Answer: B
90° phase lag.
90° phase lag.
14. Resonance when:
Answer: A
Net reactance zero.
Net reactance zero.
15. Impedance at resonance:
Answer: B
Equals resistance.
Equals resistance.
16. Current at resonance:
Answer: B
Impedance minimum.
Impedance minimum.
17. Phase angle at resonance:
Answer: A
Voltage & current in phase.
Voltage & current in phase.
18. Q‑factor relates to:
Answer: A
Resonance selectivity.
Resonance selectivity.
19. Poor PF causes:
Answer: D
Industrial disadvantage.
Industrial disadvantage.
20. Industrial PF corrected using:
Answer: A
Common PF correction method.
Common PF correction method.
