Basic Electricity Flashcards by Sophya Elkihel

The opposition offered by a coil to the flow of alternating current is called (disregard resistance.)

Inductive resistance.

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When a charging current is applied to a nickel cadmium battery, the cells emit gas.

Toward the end of the charging cycle.

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(Refer to Figure 14.) The total resistance of the circuit is

17 ohms.

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(Refer to Figure 15.) With the landing gear retracted the red indicator light will not come on if an open occurs in wire

No.19

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(Refer to Figure 64.) 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 resistor? (Note: R(t) = e^2/P

24 ohms

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(Refer to Figure 12.) Find the total resistance of the circuit.

21.2 ohms

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When referring resistance in a parallel DC circuit, which of the following statements is true?

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

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Which requires the most electrical power? (Note: 1 horsepower = 746 watts.)

A 115 horsepower, 24 volt motor which is 75 percent efficient.

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(Refer to Figure 64.) A 48 volt source is required to furnish 192 watts to a parallel circuit consisting of three resistors of equal value. What is the value of each resistor?

36 ohms

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The presence of any small amount of potassium carbonate deposits on the top of nickel-cadmium battery cells in service is an indication of

Normal operation

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Typical application for zener diodes is as

Voltage regulators

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

volts

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When different rated capacitors are connected in parallel in a circuit, the total capacitance is (Note: Ct = C1 + C2 + C3…)

Equal to the sum of all the capacitances.

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(Refer to Figure 13.) Determine the total current flow in the circuit.

1.4 amperes.

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The electrolyte of a nickel-cadmium battery is the lowest when the battery is

In a discharged condition

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Which of the following statements is/are generally true regarding the charging of several aircraft batteries together?

1) Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and changed using the constant current method.
2) Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using constant voltage method.
3) Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged sing the constant current method.

1 and 2

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Which of the following logic gates will provide an active high out only when all inputs are different?

XOR

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(Refer to Figure 8.) With an ohmeter connected into the circuit as shown, what will the ohmeter read?

10 ohms

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

6 Amps

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What is the likely result of servicing and charging nickel-cadmium and lead acid batteries together in the same service area?

Combination of both types of batteries

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Which is correct in reference to electrical resistance?

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

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A thermal switch, or thermal protector, as used in an electric motor, is designed to

Open the circuit in order to allow cooling of the motor.

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

plate area and inversely proportional to the distance between the plates.

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(Refer to Figure 16.) With power to the bus and the fuel selector switched to the right-hand tank, how many relays in the system are operating?

Three

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What does the letter Q symbolize when measuring electrical charge?

Coulomb

(Refer to Figure 10.) What is the measured voltage of the series-parallel circuit between terminals A and B?

3.0 volts

What may result if water is added to a nickel-cadmium battery when it is not fully charged?

Excessive spewing is likely to occur during the charging cycle.

In a P-N-P transistor application, the solid state device is turned on when the

Base is negative with respect to the emitter.

Diodes are used in electrical power supply circuits primarily as

Rectifiers

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

The current is stepped down by 1 to 4 ratio.

A 1-horsepower, 24 volt dc electric motor that is 80 percent efficient requires 932.5 watts. How much power will a 1-horsepower, 12-volt dc electric motor that is 75 percent efficient require? (Note: 1 horsepower = 746 watts.)

994.6 watts

(Refer to Figure 16.) Energize the circuit with the fuel tank selector switch selected to the left-hand position. Using the schematic, identify the switches that will change position

5,6,11,12,13,15,16

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

What is the purpose of the ground symbol used in electrical circuit diagrams?

To show that there is a return path for the current between the source of electrical energy and the load.

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

24 volts

The voltage drop in a circuit of known resistance is dependent on

The amperage of the circuit

A 12-volt electric motor has 1,000 watts input and 1 horsepower output. Maintaining the same efficiency, how much input power will a 24-volt, 1 horsepower electric motor require? (Note: 1 horsepower = 746 watts)

1,000 watts

(Refer to Figure 16.) The TCO relay will operate if 24-volts dc is applied to the bus and fuel tank selector is in the

Crossfeed position

Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true?

The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80 F

(Refer to Figure 11.) Find the total current flowing in the wire between points C and D

3.0 amperes

(Refer to Figure 18.) When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire

No. 4

Which term means a 0.001 ampere?

Miliampere

Electrostatic fields are also known as

Dielectric fields

If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?

Apply sodium bicarbonate solution to the affected area followed by a water rinse.

(Refer to Figure 19.) When the landing gears are up and the throttles are retarded, the warning horn will not sound if an open occurs in wire

No.6

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

At least 50 percent greater than the highest applied voltage.

In an N-D-N transistor application, the solid state device is turned on when the

Base is positive with respect to the emitter

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 amperes

(Refer to Figure 7.) If resistor R (3) is disconnected at terminal D, what will the ammeter read?

Infinite resistance

The end-of-charge voltage of a 19-cell nickel-cadmium battery, measured while still on charge

Depends upon its temperature and the method used for charging

Which of the following are commonly used as a rectifier in electrical circuits?

Diodes

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

Inductance

(Refer to Figure 2.) What is the total capacitance of a circuit containing three capacitors with capacitances of 0.02 microfarad, 0.05 microfarad, and .10 microfarad respectovely?

0.0125 microfarad

(Refer to Figure 21.) Which symbol represents a variable resistor?

0.002Kv equals

2.0 volts

What factors strengthen a coil inductor?

Adding coils close together

How many amperes 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?

25.23 amperes

A lead-acid battery with 12 cells connected in series (no-load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2-ohms resistance. The internal resistance of the battery on this instance is

0.52 ohm

What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?

The state-of-charge of the battery

A circuit has an applied voltage of 30 volts and a load consisting of a 10 ohm resistor in series with a 20 ohm resistor. What is the voltage drop across the 10 ohm resistor?

10 volts

If each cell, connected in series, equals 2 colts, how would a 12-cell lead acid battery be rated?

24 volts

What unit is used to express electrical power?

Watt

The electrolyte of a nickel cadmium battery is highest when the battery is

In a fully charged condition

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?

24 volts

Which of the following best describes the operating principal in a nickel-cadmium battery installed in an aircraft?

To completely charge a nickel-cadmium battery, some gassing must take place; thus, some water will be used.

Capacitors are sometimes used in dc circuits to

Smooth out slight pulsations in current/voltage

Which of the following best describes the contributing factors to thermal runaway in a nickel-cadmium battery installed in an aircraft?

Low internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential (voltage) charging system.

(Refer to Figure 19.) When the throttles are retarded with only the right gear down, the warning horn will not sound if an open occurs in wire

No.5

(Refer to Figure 19.) Under which condition will a ground be provided for the warning horn through both gear switches when the throttles are closed?

Left gear up and right gear down.

(Refer to Figure 11.) Find the voltage across 8-ohm resistor

24 volts

(Refer to Figure 26.) Which of the logic gate output conditions is correct with respect to the given inputs?

Convert farads to picofarads by:

multiplying farads by 10 to the power of 12.

(Refer to Figure 18.) The control valve switch must be placed in the neutral position when the landing gears are down to

Prevent the warning horn from sounding when the throttles are closed.

(Refer to Figure 20.) Troubleshooting an open circuit with a voltmeter as shown in this circuit will

Permit the battery voltage to appear on the voltmeter

(Refer to Figure 5.) What is the impedance of an ac-series circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 4 ohms, and a resistor with a resistance of 8 ohms?

10 ohms

(Refer to Figure 23.) If R(2) sticks in the up position, the light will

Be on full bright.

(Refer to Figure 17.) Which of the components is a potentiometer?

What will a voltmeter read id properly connected across a closed switch in a circuit with electrical power on?

Zero voltage

In nickel-cadmium batteries, a rise in cell temperature

Causes a decrease in internal resistance

A 14 ohm resistor us to be installed in a series circuit carrying .05 ampere. How much power will the resistor be required to dissipate?

At least 35 milliwatts

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

Inductive reactance

(Refer to Figure 24.) Which statement concerning the depicted logic gate is true?

Any input being 1 will produce a 1 output

(Refer to Figure 6.) If resistor R(5) is disconnected at the junction of R(4) and R(3) as shown, what will the ohmeter read?

3 ohms

A fully charged lead-acid battery will not freeze until extremely low temperatures are reached because

Most of the acid is in the solution.

The method used to rapidly charge a nickel-cadmium battery utilizes

Constant voltage and varying current

How can the state-of-charge of a nickel-cadmium battery be determined?

By a measured discharge

Which requires the most electrical power during operation? (Note: 1 horsepower = 746 watts)

Two lights requiring 3 amperes each in a 24-volt parallel system.

(Refer to Figure 16.) What will be the effect if the PCO relay fails to operate when the left-hand tank is selected?

The fuel pressure crossfeed valve open light will not illuminate.

Through which material will magnetic lines of force pass most readily?

Iron

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

Inductance and frequency

(Refer to Figure 15.) The no.7 wire is used to

Close the PUSH-TO-TEST circuit

(Refer to figure 15.) When the landing gear is down, the green light will not come on if an open occurs in wire

No.6

(Refer to Figure 1.) When different rated capacitors are connected in series in a circuit, the total capacitance is

Less than the capacitance of the lowest rated capacitor

In an ac circuit, the effective voltage is

Less than maximum instantaneous voltage

(Refer to Figure 4.) How much power is being furnished to the circuit?

2,645 watts

Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?

Heat or burn marks on the hardware.

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

Impedance

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) (Note: L(t) = L(1) +L(2)...)

Equal to the sum of the individual inductances.

(Refer to Figure 3.) When more than two inductors of different inductance are connected in parallel in a circuit, the total inductance is

Less than the inductance of the lowest rated inductor.

Forward biasing of a solid state device will cause the device to

Conduct

During discharge, nickel-cadmium batteries will show a lower liquid level than when at full charge because

electrolyte becomes absorbed into the plates

(Refer to Figure 9.) How many instruments voltmeters and ammeters are installed correctly?

Two

What is the basic unit of electrical quantity

Coulomb

When calculating power in a reactive or inductive ac circuit, the true powers

Less than the apparent power

(Refer to Figure 17.) The electrical symbol represented at number 5 is a variable

Capacitor

What is the total capacitance of a certain circuit containing three capacitors with capacitances of 0.25 microfarad, 0.03 microfarad, and 0.12 microfarad respectively? (Note: C(t) = C(!) +C(2)...

0.4 microfarad

(Refer to Figure 22.) Which illustration is correct concerning bias application and current (positive charge) flow?

Convert farads to microfarads by

Multiplying farads by 10 to the power of 6

Which of these will cause the resistance of a conductor to decrease?

Decrease the length or increase the cross-sectional area.

(Refer to figure 23.) If an open occurs at R(1), the light

Cannot be turned off

Which is correct concerning a parallel circuit?

Total resistance will be smaller than the smallest resistor

(Refer to Figure 16.) When electrical power is applied to the bus, which relays are energized?

DCC and TCC

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

Effective values

(Refer to Figure 25.) In a functional and operating circuit, the depicted logic gate output will be 0

When one or more inputs are 0

Which effect does not apply to the movement of elections flowing in a conductor?

Static energy

What is the total capacitance of a circuit containing three capacitors in parallel with capacitances of 0.02 microfarad, 0.05 microfarad, and 0.10 microfarad, respectivey?

.170 microfarad

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

Is called induction

The purpose of providing a space underneath the plates in a lead acid battery's cell container is to

Prevent sediment buildup from contacting the plates and causing a short circuit

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

in parallel with a unit

When referring to an electrical circuit diagram, what point is considered to be at zero voltage?

The ground reference

How much power must a 24-volt generator furnish to a system which contains the following loads? Unit: One moter 75% efficient > rating: 1/5 hp Three position lights > 20 watts each One heating element > 5 amp One anti-collision light > 3 amp (Note: 1 horsepower = 746 watts.)

450 watts

What is the operating resistance of a 30-watt light bulb designed for a 28-volt system?

26 ohms