Electricity 1

1.

1 point

a 1 hp, 24, volt DC electric motor that is 80 percent efficient requires 932.5. how much power will a 1 hp, 12 volt DC electric motor that is 75 percent efficient require?

944.6 watts

932.5 watts

1305.5 watts

2.

1 point

in a parallel circuit with three 6 ohm resistors across a 12 volt battery, what is the total current (It) value in the circuit

12 amps

6 amps

2 amps

3.

1 point

which effect does not apply to the movement of electrons flowing in a conductor

thermal energy

magnetic energy

static energy

4.

1 point

What is the opposition to the flow of AC produced by a magnetic field with generated back voltage (EMF) called?

Mutual inductance

Capacitive reactance

Inductive reactance

5.

1 point

when different rated capacitors are connected in parallel in a circuit, the total capacitance is

equal to the sum of all the capacitances

less than the capacitance of the lowest rated capacitor

equal to the capacitance of the highest rated capacitor

6.

1 point

a cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a 30 volt source. if the voltage across the 10 watt light is measured, it will be

equal to the voltage across the 20 watt light

one third of the input voltage

half the voltage across the 20 watt light

7.

1 point

which term means .001 ampere

microampere

milliampere

kiloampere

8.

1 point

the potential difference between two conductors which are insulated from each other is measured in

coulombs

amperes

volts

9.

1 point

what is the total capacitance of a certain circuit containing three capacitors with capacitances of .25 microfarad, .03 microfarad, and .12 microfarad, respectively?
(Ct = C1 + C2 + C3)

.4 uF

.04 uF

.04 pF

10.

1 point

what will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on

system voltage

zero voltage

voltage drop in the components the switch is connected to

11.

1 point

a 12 volt electric motor has 1000 watts input and 1 horsepower output. maintaining the same efficiency, how much input power will a 24 volt, 1 hp electric motor require?

1000 watts

2000 watts

500 watts

12.

1 point

what unit is used to express electrical power

ampere

watt

volt

13.

1 point

convert farads to microfarads by

multiplying microfarads by 10 to the power of 6

multiplying farads by 10 to the power of 6

multiplying picofarads by 10 to the power of 6

14.

1 point

if three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28 volt circuit, how much current will flow through the 3 ohm resistor

0.93 ampere

1.05 amperes

9.3 amperes

15.

1 point

Capacitors are sometimes used in DC circuits to

Assist in stepping voltage and current up and/or down

Counteract inductive reactance at specific locations

Smooth out slight pulsations in currect/voltage

16.

1 point

when more than two inductors of different inductances are connected in parallel in a circuit, the total inductance is

equal to the sum of the individual inductances

equal to the inductance of the highest rated inductor

less than the inductance of the lowest rated inductor

17.

1 point

a 24 volt source is required to furnish 48 watts to a parallel circuit consisting of two resistors of equal value. what is the value of each resitor?

12 ohms

24 ohms

6 ohms

18.

1 point

An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?

Resistance and capacitive reactance

Resistance and voltage

Inductance and frequency

19.

1 point

in a parallel circuit with four 6 ohm resistors across a 24 colt battery, what is the total across resistor-three (VR3) in the circuit?

18 volts

6 volts

24 volts

20.

1 point

the correct way to connect a test voltmeter in a circuit is

between the source voltage and the load

in series with a unit

in parallel with a unit

21.

1 point

when inductors are connected in series in a circuit, the total inductance is (where the magnetic fields of each inductor do not affect the others).

less than the inductance of the lowest rated inductor

equal to the sum of the individual inductances

equal to the inductance of the highest rated inductor

22.

1 point

what is the operating resistance of a 30 watt light bulb designed for a 28 volt system

1.07 ohms

26 ohms

0.93 ohm

23.

1 point

diodes are used in electrical power supply circuits primarily as

rectifiers

switches

relays

24.

1 point

which of the following are commonly used as rectifiers in electrical circuits

1. anodes
2. cathodes
3. diods

3,1

3

3,2

25.

1 point

The basis for transformer operation in the use of alternating current is mutual

Inductance

Reactance

Capacitance

26.

1 point

In an AC circuit, the effective voltage is

Equal to the maximum instantaneous voltage

Greater than the maximum instantaneous voltage

Less than the maximum instantaneous voltage

27.

1 point

Electrostatic fields are also known as

Static fields

Electrostatic fields

Dielectric fields

28.

1 point

which is correct in reference to electrical resistance

as electrical device that has a high resistance will use more power than one with a low resistance with the same applied voltage

two electrical devices will have the same combined resistance if they are connected in series as they will have if connected in parallel

if one of three bulbs in a parallel lighting circuit is removed, the total resistance of the circuit will become greater

29.

1 point

how much power must a 24 volt generator furnish to a system which contains the following loads?

one motor (75 percent efficient) 1/5 hp
three position lights 20 watts each
one heating element 5 amp
one anticollision light 3 amp

(1hp = 746 watts)

402 watts

385 watts

450 watts

30.

1 point

The amount of electricity a capacitor can store is directly proportional to the

Plate area and inversely proportional to the distance between the plates

Plate area and is not affected by the distance between the plates

Distance between the plates and inveresely proportional to the plate area

31.

1 point

unless otherwise specified, any values given for current or voltage in an AC circuit are assumed to be

effective values

maximum values

instantaneous values

32.

1 point

which statement is correct when made in reference to a parallel circuit?

the current in amperes can be found by dividing the EMF in volts by the sum of the resistors in ohms

the total current is equal to the sum of the currents through the individual branches of the circuit

the current is equal in all portions of the circuit

33.

1 point

how many amps will a 28 volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each

1.11 amperes

1 ampere

25.23 amperes

34.

1 point

What is the total capacitance of a certain circuit containing three capacitors with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectivly? (Series circuit)

.0125 uF

.170 uF

0.125 pF

35.

1 point

what is the basic unit of electrical quantity

ampere

coulomb

electromotive force

36.

1 point

The opposition offered by a coil to the flow of alternating current is called

Impedance

Inductive reactance

Reluctance

37.

1 point

which of these will cause the resistance of a conductor to decrease

decrease the length or the cross-sectional area

decrease the length or increase the cross-sectional area

increase the length or decrease the cross-sectional area

38.

1 point

which requires the most electrical power during operation

a 12 volt motor requiring 8 amps

two lights requiring 3 amps each in a 24 volt parallel system

four 30 watt lamps in a 12 volt parallel circuit

39.

1 point

.002kv equals

2.0 volts

20 volts

.2 volt

40.

1 point

a 14 ohm resistor is to be installed in series circuit carrying .05 ampere. how much power will the resistor be required to dissapate

at least 35 milliwatts

less than .035 watt

at least .70 milliwatt

41.

1 point

When different rated capacitors are connected in series in a circuit, the total capacitance is

Less than the capacitance of the lowest rated capacitor

Equal to the sum of all the capacitances

Greater than the capacitance of the highest rated capacitor

42.

1 point

what happens to the current in a voltage step-up transformer with a ratio of 1 to 4?

the current is stepped down by a 1 to 4 ratio

the current does not change

the current is stepped up by a 1 to 4 ratio

43.

1 point

a 24 volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. what is the voltage drop across each resistor

12 volts

24 volts

6 volts

44.

1 point

The working voltage of a capacitor in an AC circuit should be

Equal to the highest applied voltage

At least 50 percent greater than the highest applied voltage

At least 20 percent greater than the highest applied voltage

45.

1 point

what is the total capacitance of a circuit containing three capacitors in parallel with capacitance's of .02 microfarad, .05 microfarad, and .10 microfarad, respectively

.0125 uF

.170 uF

0.125 pF

46.

1 point

which requires the most electrical power?

a 24 volt anti collision light circuit consisting of two light assemblies which require 3 amps each during operation

a 1/5 hp, 24 molt motor which is 75 percent efficient

four 30 watt lamps arranged in a 12 volt parallel circuit

47.

1 point

convert farads to picofarads by

multiplying microfarads by 10 to the power of -12

multiplying farads by 10 to the power of 12

multiplying picofarads by 10 to the power of 12

48.

1 point

when calculating power in a reactive or inductive AC circuit, the true power is

less than the apparent power in a reactive circuit circuit and more than the apparent power in an inductive circuit

more than the apparent power

less than the apparent power

49.

1 point

The term that describes the combined resistive forces in an AC circuit is

Resistance

Impedance

Reactance

50.

1 point

transfer of electric energy from one circuit to another without the aid of electrical connections

is called induction

can cause excessive arching and heat, and as a result is practical for use only with low voltages/amperages

is called capactitance