In an alternating current (AC) circuit, the phase relationship between current and voltage depends on the circuit elements. Match the entries in Column I with the appropriate relations in Column II:
| Column I (Type of circuit) | Column II (Phase relationship between current and voltage) |
|---|---|
| i. Pure resistance (R) | p. Current leads voltage by 90° |
| ii. Pure capacitance (C) | q. Current and voltage are in the same phase |
| iii. Pure inductance (L) | r. Current and voltage may or may not be in the same phase |
| iv. R–L–C series circuit | s. Current lags voltage by 90° |
Select the correct matching option:
- Ai-p, ii-s, iii-q, iv-r
- Bi-q, ii-p, iii-s, iv-r
- Ci-q, ii-s, iii-p, iv-r
- Di-s, ii-r, iii-p, iv-q
Show answer and explanation
Correct answer: (b) i-q, ii-p, iii-s, iv-r
Explanation
In an AC circuit:
- Pure resistance: current and voltage are in the same phase (i–q).
- Pure capacitance: current leads the voltage by 90° (ii–p).
- Pure inductance: current lags the voltage by 90° (iii–s).
- R–L–C series circuit: the phase difference depends on the values of R, L and C, so current and voltage may or may not be in phase (iv–r). They are in phase at resonance.
So the code is i-q, ii-p, iii-s, iv-r.