basic electricity

80問 • 1年前

問題一覧

Electrostatic fields are also known as

Dielectric field

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

A 14-ohm resistor is 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 total capacitance of a certain circuit containing three capacitors with capacitance with capacitances of .25 microfarad, .03 microfarad, and .12 microfarad, respectively? (Note: C(T)= C(1) + C(2) + C(3))

4 μF

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

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

The electrolytes become absorbed into the plates

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

The amperage of the circuit

When referencing 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

What is the basic unit of electrical quantity?

Coulomb

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

Most of the acid is in the solution

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

Diodes

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

In a discharged condition

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

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

Inductive reactance

Typical application for Zener diodes is as

Voltage regulators

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

Zero voltage

Convert farads to picofarads by:

Multiplying farads by 10 to the power of 12

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

Toward the end of the charging cycle

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

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

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

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

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

Volts

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) + L(3)...)

Equal to the sum of the individual inductances

Which term means .001 ampere?

Milliampere

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

Is called induction

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

Static energy

What unit is used to express electrical power?

Watt

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

Impedance

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

XOR

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 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

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

Inductance and frequency

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

Base is negative with respect to the emitter

Convert farads to microfarads by

Multiplying farads by 10 to the power of 6

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

Less than the apparent power

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

By a measured discharge

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 in this instance is

0.52 ohms

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

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

6 amps

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

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 is correct concerning a parallel circuit?

Total resistance will be smaller than the smallest resistor

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

Decrease the length or increase the cross-sectional area

What does the letter Q symbolize when measuring electrical charge?

Coulomb

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

Heat or burn marks on the hardware

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

At least 50% greater than the highest applied voltage

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

In fully charged condition

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

Inductive reactance

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

Which is correct in reference to electrical resistance?

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

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

The ground reference

What factors strengthen a coil inductor?

Adding coils close together

A cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a circuit 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

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

In parallel with a unit

002KV equals

2.0 volts

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

Constant voltage and varying current

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

24 volts

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

Iron

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

Inductance

In an ac circuit, the effective voltage is

Less than the maximum instantaneous voltage.

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 charged 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 the 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 using the constant current method.

1 and 2

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 nickel-cadmium batteries, a rise in cell temperature

Causes a decrease in internal resistance

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

Conduct

Which of the following best describes the operating principle 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

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

A 1/5 horsepower, 24-volt motor which is 75 percent efficient

A 1-horsepower , 2-volt dc electric motor that is 80 percent efficient requires 932.5 watts. How much power will a 1- horspeower, 12-volt dc electric motor that is 75 percent efficient require? (Note: 1hp= 746 watts)

994.6 watts

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

1,000 watts

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

Effective values

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

Contamination of both types of batteries

When different rated capacitors are connected in parallel in a circuit, the total capacitance is (Note: C(T) = C(1) + C(2) + C(3)...)

Equal to the sum of all the capacitances

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

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

26 ohms

What is the total capacitance of a circuit containing three capacitors in parallel with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?

0.170 μF

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

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

Base is positive with respect to the emitter

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

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

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

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

M#5 Section and Title v2

ユーザ名非公開 · 32問 · 13日前

M#5 Section and Title v2