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A resistance ‘R’ Ω and inductance of ‘L’ H are connected across 240 V, Hz supply. Power dissipated in the circuit is 300 W and the voltage across R is 100 V. In order to improve the power fact or to unity, the capacitor that is to be connect ed in series should have a val ue of _______ μF
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- 11.5 μF.
- 13.7 μF.
- 12.5 μF.
- 43.7 μF.
Correct Option: D
| = 300 | ||
| R |
| ⇒ R = | = | Ω | ||
| 300 | 3 |
| ⇒ I = | = 3 amp. | ||||
 |  | ||||
| 3 | |||||
For p.f. to be equal to unity,
| I(ωL) = I | | | = VL | ||
| ωC |
| ⇒ | = √240² - 100² = 218.17 Volt | |
| ωC |
| ⇒ C = | = 43.7 × 10-6 = 43.7 μF | |
| 2π × 50 × 218.17 |
