SET 3 ECT

Question 1

Current is

Answer 1

The movement of electrons

Question 2

What is meant by the term impedance?

Answer 2

It is a measure of the opposition to AC current flow in a circuit

Question 3

What is the name of the pressure that moves electrons in aclosed circuit?

Answer 3

Voltage

Question 4

Batteries differ from fuel cells in that

Answer 4

A battery is a closed system

Question 5

One coulomb passing a point in one second is one

Answer 5

Ampere

Question 6

What does the abbreviation “RF” refer to?

Answer 6

Radio frequency signals of all types

Question 7

A communications device that combines transmissions fromseveral I/O devices into one line is a

Answer 7

Multiplexer

Question 8

How much power (roughly) a light emitting diode can couple intoan optical fiber?

Answer 8

100 microwatts

Question 9

In practical applications, battery voltage

Answer 9

Is lowered as the load increases

Question 10

What are the basic building blocks that all matter is composedof?

Answer 10

Electrons, neutrons, and protons

Question 11

If current through a resistance is halved

Answer 11

The voltage is halved

Question 12

Most data communications involving telegraph lines use

Answer 12

Narrowband channel

Question 13

Which electronics material opposes the movement of freeelectrons?

Answer 13

Insulator

Question 14

Which of the following is used to convert a radio signal from onefrequency to another?

Answer 14

Mixer

Question 15

Which voltage source converts chemical energy to electricalenergy?

Answer 15

Battery

Question 16

Which of the following battery types is rechargeable?

Answer 16

Lead-acid gel-cell
Lithium-ion ()
Nickel-metal hydride

Question 17

A basic electric circuit is made up of what components?

Answer 17

A voltage source, a load, and a conductive path for current

Question 18

How much power (roughly) a light emitting diode can couple intoan optical fiber?

Answer 18

100 microwatts

Question 19

Primary batteries, unlike secondary batteries, may be

Answer 19

Used once

Question 20

battery’s capacity to deliver power is measured in

Answer 20

Ampere hours

Question 21

Which of the following condition is used to transmit two packetsover a medium at the same time?

Answer 21

Collision

Question 22

How much power is being used in a circuit when the appliedvoltage is 13.8 volts DC and the current is 10 amperes?

Answer 22

138 watts

Question 23

Which of the following communications lines is best suited tointeractive processing applications?

Answer 23

Full duplex lines

Question 24

Which of the following types of channels moves data relativelyslowly?

Answer 24

Narrow band channel

Question 25

the resistance in a circuit with constant voltage increases, the current will

Answer 25

Decrease

Question 26

A lead-acid battery is an example of a

Answer 26

Secondary battery

Question 27

What are the three electrodes of a PNP or NPN transistor?

Answer 27

Emitter, base, and collector

Question 28

How many digits of the DNIC (Data Network Identification Code) identify the country?

Answer 28

First three

Question 29

A station in a network forwards incoming packets by placing them on its shortest output queue. What routing algorithm is being used?

Answer 29

Hot potato routing

Question 30

An example of potential energy is

Answer 30

A battery

Question 31

Which part of an atom has no electrical charge?

Answer 31

Neutron

Question 32

What do you call a diagram that shows the electrical connections of a circuit's components?

Answer 32

A schematic diagram

Question 33

If an electrical system is compared to a fluid system, the electrical current corresponds to the

Answer 33

Water flow  

Question 34

In a synchronous modem, the digital-to-analog converter transmits signal to the

Answer 34

Equilizer

Question 35

What are the units of impedance?

Answer 35

Ohms

Question 36

What is the kilowatt-hour consumption of a 40 W lamp if it remains on for 1750 h?

Answer 36

70

Question 37

Which of the following types of channels moves data relatively slowly?

Answer 37

Narrow band channel

Question 38

What is the minimum number of wires needed to send data over a serial communication link layer?

Answer 38

2

Question 39

Which of the following statement is correct? Transmission section of a synchronous modem contains the scrambler  

Question 40

What is a transceiver?

Answer 40

A unit combining the functions of a transmitter and a receiver  

Question 41

Which of the following battery types is not rechargeable?

Answer 41

Carbon-zinc

Question 42

The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to

Answer 42

0.009

Question 43

Which data communication method is used to transmit the data over a serial communication link?

Answer 43

full-duplex

Question 44

When does maximum power transfer happen from the source to the load?

Answer 44

When the source resistance equals the load resistance

Question 45

The synchronous modems are more costly than the asynchronous modems because

Answer 45

They contain clock recovery circuits

Question 46

If 60 J of energy are available for every 15 C of charge, what is the voltage?

Answer 46

4 V

Question 47

Frames from one LAN can be transmitted to another LAN via the device

Answer 47

Bridge

Question 48

Which term describes the ability of a receiver to detect the presence of a signal?

Answer 48

Sensitivity

Question 49

What at are the three electrodes of a field effect transistor?

Answer 49

Source, gate, and drain

Question 50

A secondary cell generates dc via chemical activity; a primary cell generates dc

Answer 50

Chemically

Question 51

Which of the following precautions should be taken when measuring high voltages with a voltmeter?

Answer 51

Ensure that the voltmeter and leads are rated for use at the voltages to be measured