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In an electrical circuit R, L, C and an a.c. voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage the current in the circuit is π/3. If instead, C is removed from the circuit, the phase difference is again π/3. The power factor of the circuit is :
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- 1/2
- 1/√2
- 1
- √3 / 2
Correct Option: C
when L is removed from the circuit
| Xc | = tan | π | |
| R | 3 |
| Xc = R tan | π | ...(1) |
| 3 |
when C is remove from the circuit
| XL | = tan | π | |
| R | 3 |
| Xc = R tan | π | ...(2) |
| 3 |
net impedence Z = √R² + (XL - XC)² = R
| power factor cos φ = | = 1 | |
| Z |
