In the circuit shown in the figure, what value of C will

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In the circuit shown in the figure, what value of C will cause a unity power factor at the ac source?

1. 68.1F
2. 165 F
3. 0.681 F
4. 6.81 F

Correct Option: A

At u.p.f. operation admittance of both branches

Y = jωC +	1
	30 ∠40

= jωC +	1
	30 (0.76 + 0.64j)

Equalizing imaginary part, we get C = 68.1 μF.