Find answer to the following question.     1. In a three-phase system, the voltages are separated by
	A. 45° B. 90° C. 120° D. 180°

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2.	In a three-phase system, when the loads are perfectly balanced, the neutral current is
	A. zero B. one-third of maximum C. two-thirds of maximum D. at maximum

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3.	In a -connected source driving a -connected load, the
	A. load voltage and line voltage are one-third the source voltage for a given phase B. load voltage and line voltage are two-thirds the source voltage for a given phase C. load voltage and line voltage cancel for a given phase D. load voltage, line voltage, and source phase voltage are all equal for a given phase

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4.	In a certain three-wire Y-connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages are
	A. 2,000 V B. 6,000 V C. 666 V D. 3,464 V

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5.	In a -connected source feeding a Y-connected load,
	A. each phase voltage equals the difference of the corresponding load voltages B. each phase voltage equals the corresponding load voltage C. each phase voltage is one-third the corresponding load voltage D. each phase voltage is 60° out of phase with the corresponding load voltage
6.	In a Y-Y source/load configuration, the
	A. phase current, the line current, and the load current are all equal in each phase B. phase current, the line current, and the load current are 120° out of phase C. phase current and the line current are in phase, and both are 120° out of phase with the load current D. line current and the load current are in phase, and both are out of phase with the phase current

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7.	In a Y-connected circuit, the magnitude of each line current is
	A. one-third the phase current B. three times the corresponding phase current C. equal to the corresponding phase current D. zero

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8.	A constant load power means a uniform conversion of
	A. mechanical to electrical energy B. electrical to mechanical energy C. current to voltage D. voltage to current

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9.	Referring to Problem 3, power consumption is
	A. 16 W B. 160 mW C. 160 W D. 3,459 W

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10.	A two-phase generator is connected to two 90 load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?
	A. 1.33 A B. 1.88 A C. 2.66 A D. 1.77 A
11.	A single-phase sinusoidal voltage of 120 V is connected to a 90 load. Current in the circuit is
	A. 13.3 mA B. 133 mA C. 1.33 A D. 6.2 A

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12.	A three-phase generator is connected to three 90 load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?
	A. 0 A B. 1.33 A C. 3.99 A D. 2.66 A

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13.	Compare the total copper cross sections in terms of current-carrying capacity for a single-phase and a three-phase 120 V system with effective load resistance of 15 .
	A. single-phase 32 A; three-phase 16 A B. single-phase 16 A; three-phase 8 A C. single-phase 8 A; three-phase 4 A D. single-phase 16 A; three-phase 0 A

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14.	If in a Y-connected ac generator, each phase voltage has a magnitude of 90 VRMS, what is the magnitude of each line voltage?
	A. 0 V B. 90 V C. 156 V D. 180 V

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15.	Referring to Problem 3, the total copper cross section must handle
	A. 1.33 A B. 2.66 A C. 266 mA D. 26.6 mA
16.	Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated by
	A. certain constant phase angles B. certain constant frequencies C. certain constant voltages D. certain constant currents

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17.	In a balanced three-phase load, each phase has
	A. an equal amount of power B. one-third of total power C. two-thirds of total power D. a power consumption equal to IL

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18.	In a certain Y-Y system, the source phase currents each have a magnitude of 9 A. The magnitude of each load current for a balanced load condition is
	A. 3 A B. 6 A C. 9 A D. 27 A

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19.	A three-phase -connected generator is driving a balanced load such that each phase current is 12 A in magnitude. When I θa = 12 30° A, what are the polar expressions for the other phase currents?
	A. I θb = 12 150° A, I θc = 12–90° A B. I θb = 12120° A, I θc = 1230° A C. I θb = 1230° A, I θc = 12120° A D. I θb = 1290° A, I θc = 1290° A

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20.	In a Y-connected circuit, between each line voltage and the nearest phase voltage, there is a phase angle of
	A. 0° B. 30° C. 60° D. 120°
21.	The most common type of ac motor is the
	A. single-phase induction motor B. two-phase induction motor C. three-phase induction motor D. two-phase squirrel-cage motor

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22.	In a Y-connected source feeding a -connected load,
	A. each phase of the load has one-third of the full line voltage across it B. each phase of the load has two-thirds of the full line voltage across it C. each phase of the load has the full line voltage across it D. each phase of the load has a voltage across it equal to

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23.	Referring to Problem 6, the total copper cross section must handle
	A. 1.33 A B. 2.66 A C. 1.88 A D. 4.54 A

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24.	In a -connected generator, all of the phase voltages are
	A. zero B. equal in magnitude C. one-third of total D. one-sixth of total