Circuits and Circuit Theory

1.Inductance of a coil Varies

1. directly as the cross-sectional area of magnetic core
2. directly as square of number of turns
3. directly as the permeability of the core
4. inversely as the length of the iron path
5. as (a) to (d)

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2.A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to

1. average voltage
2. r.m.s. voltage
3. peak voltage
4. none of the above

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3.A parallel AC. circuit in resonance will

1. have a high voltage developed across each inductive and capacitive section
2. have a high impedance
3. act like a resistor of low value
4. have current in each section equal to the line current

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4.A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to

1. the capacitive reactance in ohms
2. the current flowing in capacitor
3. the size of the capacitor being quite big
4. the statement is incorrect

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5.A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be attributed to

1. the big size of the inductor
2. the reactance of the inductor
3. the current flowing in the inductor
4. the statement given is false

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6.A sine wave has a frequency of 50 Hz. Its angular frequency is _________ radian/second.

1. 100 n
2. 50 jt
3. 25 JT
4. 5 n

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7.All definitions of power factor of a series R-L-C circuit are correct except

1. ratio of net reactance and impedance
2. ratio of kW and kVA
3. ratio of J and Z
4. ratio of W and VA

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8.All the rules and laws of D.C. circuit also apply to A.C. circuit containing

1. capacitance only
2. inductance only
3. resistance only
4. all above

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9.An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms,

1. the current through the resistance is more
2. the current through the resistance is less
3. both resistance and inductance carry equal currents
4. none of the above

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10.Aphasoris

1. a line which represents the magnitude and phase of an alternating quantity
2. a line representing the magnitude and direction of an alternating quantity
3. a coloured tag or band for distinction between different phases of a 3-phase supply
4. an instrument used for measuring phases of an unbalanced 3-phase load

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