IDA-101 End of unit 7

Alternating current is _______.

• commonly produced using batteries

• electrons reversing their flow at regular intervals

• the most commonly used current

• electrons that flow continuously in one direction

What is the advantage of alternating current over direct current?

Direct current is used in which of the following applications in the industry?

• electronic control components

• magnetic starters

• three-phase motors

• none of the choices are correct

What is the common frequency of alternating current in the United States?

• 25 hertz

• 50 hertz

• 60 hertz

• 120 hertz

What is reactance?

• the resistance to the changing flow of alternating current

• A type of chemical reaction

• A form of resistance in DC circuits

• A unit of electrical current

What is impedance?

• is the sum of the resistance and reactance in A/C.

• A type of electrical current

• A unit of power

• A type of circuit

What is the sum of the resistance and reactance in an alternating current?

• induction

• alternation

• impedance

• none of the choices are correct

Give a brief description of the transmission of alternating current from the generating plant to the consumer.

• Alternating current is transmitted at high voltages and transformed to the desired voltage.

• Alternating current is transmitted at low voltages to ensure safety.

• Alternating current is transmitted using direct current lines.

• Alternating current is transmitted without any transformers.

Name the four voltage-current characteristics commonly used today.

• 230v/single phase/60H

  208v/three phase/60H

  230v/three phase/60H

  480v/three phase/60H

• 230v/single phase/50H

  208v/three phase/50H

  230v/three phase/50H

  480v/three phase/50H

• Ohm's Law, Kirchhoff's Law, Faraday's Law, Ampere's Law

• Ohm's Law, Norton's Theorem, Coulomb's Law, Thevenin's Theorem

The phase of alternating current is _______.

• the number of current alternating at different time intervals in an A/C circuit.

• direct current

• constant

• static