169.  While drawing vector diagram for a series circuit, the reference vector is
A. voltage
B. current
C. power
D. phase angle

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170.  For a purely resistive circuit the following statement is in correct
A. Work done is zero
B. Power consumed is zero
C. Heat produced is zero
D. Power factor is unity

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171.  What inductance will give the same reactance as a capacitor of 2 p F when both are at 50Hz?
A. 5 H
B. 10 H
C. 15 H
D. 20 H

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172.  In an A.C. circuit I sin is called
A. active component
B. wattless component
C. any of the above
D. none of the above

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173.  In a R-L-C circuit the impedance is given by
A. Z = R+ XL ?Xc
B. Z = R - XL + Xc
C.Z= ii(R+ XL)2 + Xc2
D.Z = 11112 + (XL - Xc)2

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174.  Analternating voltage V = 160 + j 120 V is applied to a circuit and the subsequent current flowing I = -6 + j 15 A. The impedance of the circuit is
A. 12 -j 3.2
B. 3.2 - j 12
C. 6.4 - j 24
D. none of the above

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175.  The impedance 3.2 - j12 in polar form is given as
A. 6.4 L - 75?
B. 8.4 L - 75?
C. 10.4 L-75?
D. 12.4 L - 75?

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