TRC NGHIM ANH VN CHUYN NGNHUnit 1 Batteries1. Type of zinc-carbon cells is __________a. Primary b. Secondaryc. Masterd. slave2. Type of NiCad cells is __________a. Primary b. Secondary c. Masterd. slave3. The positive electrode of zinc-carbon cells is made of __________a. Zincb. Mercuryc. Carbond. manganese dioxide. 4. The negative electrode of zinc-carbon cells is made of __________a. Zinc b. Carbonc. Mercuryd. manganese dioxide.5. The positive electrode ofNiCad cells is made of __________a. Cadmiumb. Nickel c. Nitrogend. calcium6. The negative electrode of zinc-carbon cells is made of __________a. Cadmium b. Nickle c. Calciumd. nitrogen7. A zinc-carbon cell is the most popular cell for low-current or occasional use, e.g. __________a. in torches. b. in torches only.c. in radio sets only.d. in portable phones only.8. The electrolyte of zinc-carbon cells is __________a. ammonium chloride. b. potassium hydroxide.c. sodium hydroxide.d. sodium chloride.9. The electrolyte ofNiCad cells is __________a. ammonium chloride. b. potassium hydroxide.

c. sodium hydroxide.d. sodium chloride.10. Theelectromotive forceof zinc-carbon cells is __________a. 1.2 V. b. 1.5 V. c. 1.8 V.d. 2.1 V11. The electromotive force ofNiCad cells is __________a. 1.2 V. b. 1.5 V. c. 1.8 V.d. 2.1 V12. Electromotive force means __________a. voltage produced by an electrical source. b. currentproduced by an electrical source.c. the tension of an electrical source.d. the motion due to an electrical source.13. __________is used to vary capacitance in a circuit.a. A variable capacitor b. A variable resistorc. A capacitord. A resistor14. __________ is used to rectify alternating current.a. A transformerb. A resistorc. A capacitord. A diode 15. __________ is used to add resistance to a circuit.a. An inductorb. A diodec. A resistor d. A capacitor 16. __________ is used to measure very small currents.a. An ammeterb. A volmeterc. A milliammeter d. A millivoltmeter17. __________ is used to break a circuit.a. Afuseb. A switch c. A dioded. A transistor18. __________ is used to protect a circuit.a. A fuse b. A transformerc. A resistord. A switch19. __________ is used to vary the current in a circuit.a. A variable capacitorb. A variable resistor c. A capacitord. A resistor20. __________ is used to step AC voltage up or down.a. A rectifierb. A diodec. A transformer d. A voltmeter21. __________ is used to receive RF signals.a. An aerial b. An RF tunerc. An earth wired. A detector22. __________ is used to measure voltage.a. An ammeterb. A voltmeter c. A microammeterd. A milliammeter23. Cells __________ chemical energy into electricity.a. Invertb. Transformc. Change d. Transmit 24. The following nouns end in -er or -or. Pick up the best choice.a. Oscillator, transmittor, transformer, charger, rectifier, processor, amplifier, collector, detector and tuner.b. Oscillator, transmitter, transformor, charger, rectifier, processor, amplifier, collector, detector and tuner.c. Oscillator, transmitter, transformer, charger, rectifier, processor, amplifier, collector, detector and tuner. d. Oscillator, transmitter, transformer, charger, rectifier, processor, amplifier, collector, detecter and tuner.25. The power __________ an electronic circuit is normally provided by an AC mains power supply.a. to maintainb. to controlc. for controllingd. to drive 26. The powerto drivean electronic circuit is normally provided by an AC mains power supply __________ batteries are often used for portable equipment.a. Althoughb. But c. Becaused. or27. Recharging is done using a battery charger which consists of a mains power supply with a DC output __________ the required battery EMF.a. much smaller thanb. slightly smaller thanc. much larger thand. slightly larger than 28. A current is driven through the battery __________its normal output current.a. in the same directionb. in the same direction asc. in the opposite direction to d. in the opposite direction29. A fuse is connected in the live side of the supply_________ the transformera. Protectb. to protect c. drived. to drive30. An aluminium heatsink is often used__________ the diodes from overheating.a. Preventb. Avoidc. to keep d. to stem

Unit 2 Audio recording systems1. Recording system of LPs is __________a. analogue. b. digital.c. serial.d. random.2. Recording system of CDs is __________a. analogue.b. digital. c. serial.d. random. 3. Sound quality of LPs __________a. is poorer than the original. b. are poorer than the original.c. does not deteriorate with use.d. do not deteriorate with use.4. Sound quality of CDs __________a. is poorer than the original. b. are poorer than the original.c. does not deteriorate with use. d. do not deteriorate with use.5. Access of LPs is __________a. serial. b. random.c. parallel.d. digital. 6. Access of CDs is __________a. serial. b. random. c. parallel.d. analogue. 7. Material often used to make LPs is __________a. vinyl. b. perspexc. rubberd. wood8. Material often used to make CDs is __________a. vinyl. b. Perspex c. rubberd. wood9. The playing mechanism ofLPs is __________a. Eletricalb. Chemicalc. Opticald. Mechanical 10. The playing mechanism of CDs is __________a. Eletricalb. Chemicalc. Optical d. Mechanical 11. What problems are there with records ?a. 'Crackle' caused by dust and static only.b. 'Jumping' due to scratches on the recording surface only.c. Not only 'crackle' caused by dust and static but also 'jumping' due to scratches on the recording surface.d. 'Crackle' caused by dust and static, 'jumping' due to scratches on the recording surface and more other problems 12. A gramophone record means __________a. arubber disc usedto store audio recordings.b. aceramic disc usedto store audio recordings.c. avinyl disc used for storing audio recordings. d. aperspex disc used for storing audio recordings.13. A digital recording system, __________ a compact disc system, was introduced in 1982.a. such asb. meant asc. called asd. known as 14. The CD system uses a laser __________ mechanism in which a laser beam reads marks on the surface of a specially prepared perspex disc.a. Optical b. Mechanicalc. Chemicald. electrical15. Choose the false statement.a. In audio recording systems, the sound can be reproduced by spinning the record and using the movement of a metal needle in the groove to produce varying magnetic fields.b. A typical CD has a bout 20,000 circular tracks and a maximum recording capacity of 74 minutes.c. A typical LP (long-playing record) has a recording capacity of45 minutes.d. In a CD system, a recording is made by cutting a continuous groove in a perspex disk. 16. Choose the false statement.a. In a CD system, a recording is made by electronically sampling the sound 44,100 times every seconde.b. In a CD system, the audio pattern is represented by the length of the pits and the distance between them.c. In an analogue recording system, the shape of the sides of the groove represents the audio pattern.d. To playback the recording of CDs, the disc is made to revolve atdifferent speeds and a laser beam is directed at its surface. 17. Mains frequency interference __________ hum.a. result inb. results in c. result fromd. results from18. Distortion _________ too high a recording level.a. Causedb. is caused by c. are caused byd. are caused19. Noise generated within components _________ hiss.a. are due tob. due toc. is due to d. are due20. Overheating a transistor ___________ damage.a. causes ofb. cause ofc. is the cause of d. are the cause of21. A build-up of oxide on the head__________ the tape rubbing againts the head.a. leads to b. leadsc. led tod. is led to22. Poor recordings __________ dirty heads.a. is the cause ofb. is the effect ofc. are the effect of d. are the cause of 23. Interference on radios __________ unwanted signals.a. result fromb. results from c. result ind. results24. Dust on records __________ crackle.a. is caused byb. are caused byc. causes d. cause25. Automatic doors ___________ places such as airports, supermarkets, and hospitals.a. is used inb. are used in c. is used tod. are used to 26. Ifautomatic doors are fitted with a microwave sensor, it __________movement.a. Detectedb. Detects c. would have detectedd. detect27. __________ the doors are switched on, a microwave transmitter sends out a microwave beam.a. Duringb. Whilec. When d. In case of 28. If the doors are fitted with a time-delay mechanism, __________ open for about four seconds before closing again.a. it remainsb. they remain c. it would have remaindedd. they would have remainded29. If the microprocessor detects the frequency reflected back to the sensor to be varied, __________ the motor open the door.a. they would have instructedb. it would have instructedc. they instructd. it instructs 30. __________ the beam is in a semicircular pattern, the doors open when you approach from any angle.a. Because ofb. Because c. In spite ofd. Despite

Unit 3 Test and repair instruments

1. Which of the instruments would you use to check a fuse ?a. A multimeter.b. A logic probe.c. An oscilloscope.d. A function generator.2. Which of the instruments would you use to determine the frequency respone ofan audio amplifier ?a. A multimeter.b. A logic probe.c. An oscilloscope.d. A function generator.3. Which of the instruments would you use to test for the presence of a controlsignal on the output pin of a computer chip ?a. A multimeter.b. A logic probe.c. An oscilloscope.d. A function generator.4. Which of the instruments would you use to determine the value of the currentthrough a transformer ?a. A multimeter.b. A logic probe.c. An oscilloscope.d. A function generator.5. Which of the instruments would you use to measure the frequency of anoscillator ?a. A multimeter.b. A logic probe.c. An oscilloscope.d. A function generator.6. Multimeter is an instrument which can be used __________a. to measure a number of different electrical quantities, such as voltage,current, and resistance, i.e. it is a combined voltmeter, ammeter, andohmmeter.b. for measuring voltage levels and pulses in digital logic circuits.c. to measure fast-moving signals.d. to test and adjust a variety of electronic equipment such as audioamplifier.7. Logic probe is an instrument which can be used __________a. to measure a number of different electrical quantities, such as voltage,current, and resistance, i.e. it is a combined voltmeter, ammeter, andohmmeter.b. for measuring voltage levels and pulses in digital logic circuits.c. to measure fast-moving signals.d. to test and adjust a variety of electronic equipment such as audioamplifier.8. Oscilloscope is an instrument which can be used __________a. to measure a number of different electrical quantities, such as voltage,current, and resistance, i.e. it is a combined voltmeter, ammeter, andohmmeter.b. for measuring voltage levels and pulses in digital logic circuits.c. to measure fast-moving signals.d. to test and adjust a variety of electronic equipment such as audioamplifier.9. Function generator is an instrument which can be used __________a. to measure a number of different electrical quantities, such as voltage,current, and resistance, i.e. it is a combined voltmeter, ammeter, andohmmeter.b. for measuring voltage levels and pulses in digital logic circuits.c. to measure fast-moving signals.d. to test and adjust a variety of electronic equipment such as audioamplifier.10. Multimeters can have analogue or digital displays and can be switched to__________ measuring ranges.a. Differb. Differingc. Differenced. Different11. When the probe is placed on the pin of a logic IC, small colour LEDs light up toindicate if a pulse is directed or __________ the pin is at a high or a low logiclevel.a. Andb. Whetherc. Butd. So12. Televisions __________ computers, radar systems, and oscilloscopes use acathode ray tube (CRT) to prodice an output display.a. Andb. Alsoc. as well asd. or13. Which of the sections is the main section of a cathode ray tube (CRT) ?a. An electron gun.b. A deflection sysem.c. A screen with a phosphor coating.d. All of them.14. Which of the sections is the main section of a cathode ray tube (CRT) ?a. None of them.b. A heater filament.c. A control panel.d. An electromagnetic coil.15. Oscilloscopes use charged metal __________ to give an electrostatic deflection.a. Plateb. Platesc. Tubed. Tubes16. In oscilloscopes, the electron beam hits the screen, making the phosphor glowand causing a spot ___________a. to display.b. to be displayed.c. for displaying.d. be displayed.17. In oscilloscopes, the electron beam hits the screen, making the phosphor__________ and causing a spot to be displayed.a. Glowb. to glowc. be glowedd. to be glowed18. Choose the false statement.a. A magnetic field is set up in the speaker coil making it vibrate.b. The coil pushes and pulls the speaker cone causing sound waves to beproduced.c. A voltage is applied to the Y-plates making the electron beam bedeflected.d. Current flows through the filament causing the screen to glow.19. Choose the false statement.a. A magnetic field is set up in the speaker coil making it vibrate.b. The coil pushes and pulls the speaker cone causing sound waves to beproduced.c. A voltage is applied to the Y-plates making the electron beam behorizontally deflected.d. Current flows through the filament causing it to glow.20. What do we call equipment for scanning the human body for disease ?a. A scanner.b. A speech synthsizer.c. A power amplifier.d. A filter.21. What do we call equipment for sensing vibration ?a. A speech synthesizer.b. A power amplifier.c. An RF amplifier.d. A vibration sensor.22. In the CRT of oscilloscopes, the function of the electron gun is __________a. to emit a stream of electrons.b. to receive a stream of electrons.c. to hit the screen.d. to strike the screen.23. The oscilloscope has a timebase generator __________ a sawtooth wave output.a. which produceb. which producesc. produced. produces24. After __________ the electron gun, the electron beam is deflected by two pairsof parallel metal plates.a. Leavedb. Leavesc. Leaved. Leaving25. A large build-up of negative charge could be caused by the electron beam__________ the phosphor screen.a. Hitb. Hittingc. to hitd. for hitting26. A piece of transparent plastic, __________ a graticule is attached to the front ofthe screen.a. called asb. known asc. knownd. which knows27. The X and Y deflections of the electron beam cause the signal __________ in theform of a wave.a. being measured and be displayedb. be measured to be displayedc. being measured to be displayedd. being measured, be displayed28. When the electron beam reaches the right side of the screen, it __________ tothe left side again.a. rapid returnb. rapid returnsc. rapidly returnd. rapidly returns29. If the oscilloscope has an astigmatism control, it __________ vary the voltageon the third anode.a. will be used tob. would be used toc. is used tod. be used to30. The shape of the spot on the screen to be adjusted to __________ perfectlyround.a. making itb. make itc. cause itd. causing it

Unit 4 High definition television1. The aim of high definition television (HDTV) is __________ the viewer with more realistic images than are offered by today's television set.a. to provide b. providedc. providingd. provide2. The optimal viewing distance for HDTV is three times the __________ of the screen compared with seven times the present televisions.a. Highb. Height c. Talld. Tallness 3. The term HDTV is used in __________a. USAb. Japanc. Europe d. USA, Japan and Europe.4. The term ATV, Advanced Television, is used in __________a. USA b. Japanc. Europe d. USA, Japan and Europe.5. The term Hi-Vision is used in __________a. USA b. Japan c. Europe d. USA, Japan and Europe.6. In a new generation of television sets, picture quality will be excellent, crisp, and without flicker, as good as those are used __________ in the cinema.a. Seeingb. byseeingc. to seeing d. to see 7. In the HDTV system, their wide frequency ranges__________ digital, rather than analog signals.a. it to transmitb. it to transmittingc. it is possible to transmitd. it possible to transmit 8. What controls the movement of the spot of light across a television screen ?a. Theline scan signal. b. The field scan signal.c. The Y-plates.d. The X-plates. 9. What controls the movement of the spot of light down a television screen ?a. The line scan signal.b. The field scan signal. c. The Y-plates.d. The X-plates.10. What name is given to the rapid movement of the spot back to across the screen to the start of the next line ?a. The term 'back beam'.b. The term 'back ray'.c. The term 'back line'.d. The term 'flyback'. 11. How many lines are used to build up a frame in present European television systems ?a. 625 lines per frame. b. 500 lines per framec. 700 lines per framed. 1250 lines per frame 12. What happens to a screen if the frame is not scanned at least forty times per second ?a. Scatching.b. Jumping.c. Flickering. d. Slipping.13. A television picture__________ gradually by moving a spot of light across and down a screen in a raster pattern.a. built upb. builds upc. is built up d. are built14. The video signal causes the brightness of the spot __________ in propotion to the intensity of line in the original image.a. to varyingb. to vary c. varyd. varying15. Each complete image or frame __________ a minimum of 500 lines to give a picture of acceptable quality.a. are requiredb. is requiredc. requiredd. requires 16. The movement of the spot down the screen is controlled by __________a. the X-plates.b. the line scan signal.c. the field scan signal. d. the Y-plates.17. The movement of the spot across the screen is controlled by __________a. the Y-plates.b. the line scan signal. c. thefield scan signal.d. the X-plates.18. The frame must be scanned at least forty times per second to prevent the screen from _________a. jumping.b. flickering. c. slipping.d. scratching.19. The present European television system has a frame scan rate of __________a. 50 Hz. b. 45 Hz.c. 40 Hz.d. 60 Hz.20. The video signal __________ line and field sync pulses to make sure that the TV receiver starts a new line and a new frame at the same time as the TV camera.a. Contains b. Containedc. is containedd. are contained21. The video signalcontains line and field sync pulses to make sure that the TV receiver starts a new line and a new frame __________the TV camera.a. at the same time such asb. at the same time as c. such asd. like22. To allow the video signal _________ a smaller range of frequencies, each frame is transmitted in two separate halves, known as fields.a. be transmitted by usingb. be transmitted usingc. to be transmitted using d. transmitted using23. Although the fields are displayed one after the other, it happens __________ quickly that the human eye sees them as one complete picture.a. So b. Suchc. Tood. such as24. Choose the false statement.a. A television picture is built up gradually by a moving spot.b. The spot strikes the television screen causing the phosphor coating to emit light which varies in brightness according to the intensity of the original image.c. The present European system sweeps the screen in a series of 625 closed-spaced lines to ensure a good quality picture.d. When the spot reaches the left side of the screen, it is blanked and moved rapidly back to the right side in a movement called flyback. 25. Chose the false statement.a. A television picture is built up immediately by a moving spot. b. The spot strikes the television screen causing the phosphor coating to emit light which varies in brightness according to the intensity of the original image.c. The present European system sweeps the screen in a series of 625 closed-spaced lines to ensure a good quality picture.d. When the spot reaches the right side of the screen, it is blanked and moved rapidly back to the left side in a movement called flyback.26. The movement across the screen is controlled by the line scan signal_________ the movement down the screen is controlled by the field scan signal.a. While b. Duringc. Whend. since27. Study this sentence.The light varies in brightness according to the intensity of the original imagea. 'The term 'according to' is a preposition. b. 'The term 'according to' is a conjunction.c. 'The term 'according to' is a present participle verb.d. 'The term 'according to' is agerund. 28. Study this sentence.The video signal causes the brightness of the spot to vary in propotion to the intensity of light in the original image.a. The term 'in propotion to' is an adverb.b. The term 'in propotion to' is a conjunctionc. The term 'in propotion to' is a preposition. d. The term 'in propotion to' is a relative pronoun.29. The first time the spot travels down the screen it displays the first field, which _________ the even-numbered frame lines.a. Consistb. Consistsc. consist ofd. consists of 30. The rapid movement back to a starting position is__________ flyback.a. Knewb. known as c. knownd. know31. High-tech machines leave many owners baffled, according to __________ by electrical retailers.a. a survey b. surveyc. surveyingd. surveyed

Unit 5 Video cassette recorder1. High-tech machines leave many owners baffled, according to __________ by electrical retailers.a. a survey b. surveyc. surveyingd. surveyed2. High-tech machines __________owners baffled, according to a survey by electrical retailers.a. leave muchb. leave many c. leaves muchd. leaves many3. The step from recording sound on magnetic tape to __________ the same with video signals is one of increased band width.a. Dob. Doesc. Doing d. done4. The step from recording sound on magnetic tape to doing the same with video signals __________ one of increased band width.a. which areb. which isc. ared. is 5. Early reel-to-reel machines used one-inch wide tape and made the most of the available band width by moving the tape past the head at high speed.a. past is a preposition. b. past is a verb.c. past is a conjunction.d. past is a relative pronoun.6. Early reel-to-reel machines used one-inch wide tape and made the most of the available band width by __________ the tape past the head at high speed.a. Moveb. Moving c. Movedd. moves7. Improvements in magnetic tape and the use of helical scanning meant that far more data could be crammed into smaller area.a. that far more data could be crammed into smaller area is an adverb clause.b. that far more data could be crammed into smaller area is an adjectiveclause.c. that far more data could be crammed into smaller area is a noun clause. d. that far more data could be crammed into smaller area is a main clause.8. By spinning the head at a high speed, the rate at which the data could be stored or retrieved __________.a. were increasingb. were increasedc. was increasingd. was increased 9. Aligning the head at an angle to the tape laid down the information as __________ of slanted tracks.a. a series b. seriesc. sequenced. sequences10. Early VCRs were playback-only, but by building in a full-colour TV tuner, programmes could be recorded from the air __________ another channel was being viewed on a normal TV.a. While b. Duringc. Whend. at11. Early VCRs were playback-only, but by __________ in a full-colour TV tuner, programmes could be recorded from the air while another channel was being viewed on a normal TV.a. Buildb. Building c. Builtd. builds12. The inclusion of a timer meant that recordings could be made and viewed at a late date.a. that recordings could be made and viewed at a late date is an adjectiveclause.b. that recordings could be made and viewed at a late date is an adverbclause.c. that recordings could be made and viewed at a late date is a noun clause. d. that recordings could be made and viewed at a late date is a main clause.13. The inclusion of a timer meant that __________ could be made and viewed at a late date.a. Signalb. Recordedc. Recordingd. Recordings 14. The lastest VCRs allow a large number of on/off programmed times to be set __________ viewers can go on holiday and not miss a single episode of their favourite soap opera.a. in order tob. so that c. sod. to 15. The lastest VCRs allow a large number of on/off programmed times __________ so that viewers can go on holiday and not miss a single episode of their favourite soap opera.a. be settingb. be setc. to be set d. set16. Out of the VCR, the reels of a VHS tape are locked and the tape __________ by a flap.a. Coversb. Coverc. is covered d. arecovered17. Once in the VCR, the reels become unlocked and the tape guard __________ the tape.a. lifts up to expose b. lift up to exposec. lifts up to exposingd. lift up to exposing18. Once in the VCR, the reels become __________ and the tape guardlifts up to expose the tape.a. Unlockingb. Unlocked c. be unlockingd. to be unlocked19. Pressing the play or record buttons causes the tape-loading rollers __________ a length of tape from the cassette and wrap it around the head drum.a. Pulledb. be pullingc. to pull d. to be pulled20. Pressing the play or record buttons __________ the tape-loading rollers to pull a length of tape from the cassette and wrap it around the head drum.a. to causeb. to be causedc. caused. causes 21. On most VCRs audio information is transferred via a static audio head which puts information ona separate track from the video signal.a. which puts information ona separate track from the video signal is an adjective clause. b. which puts information ona separate track from the video signal is an adverbclause.c. which puts information ona separate track from the video signal is a mainclause.d. which puts information ona separate track from the video signal is a noun clause.22. On most VCRs audio information is transferred via a static audio head which __________ information on a separate track from the video signala. Putb. Puts c. Puttingd. putted23. On most VCRs audio information __________ via a static audio head which puts information on a separate track from the video signal.a. istransferringb. are transferringc. is transferred d. are transferred24. Design change:Improvements in magnetic tape and the use of helical scanning.Result:a. The cassette tape could be narrower and the tape could move at a slower speed.b. Recordings could be made and viewed at a later date.c. The rate at which the data could be stored or retrieved was increased.d. Far more data could be crammed into a smaller area. 25. Design change:Spinning the head at a high speed.Result:a. The rate at which the data could be stored or retrieved was increased. b. Recordings could be made and viewed at a later date.c. Far more data could be crammed into a smaller area.d. The modern VCR could be produced. 26. Design change:Aligning the head at an angle to the tape.Result:a. Recordings could be made and viewed at a later date.b. The information was laid down as a series of slanted tracks. c. The modern VCR could be produced.d. Far more data could be crammed into a smaller area. 27. Design change:Recording information in slanted tracks.Result:a. The modern VCR could be produced.b. Far more data could be crammed into a smaller area.c. The cassette tape could be narrower and the tape could move at a slower speed. d. The information was laid down as a series of slanted tracks.28. Design change:The inclusion of a timer.Result:a. The rate at which the data could be stored or retrieved was increased.b. The cassette tape could be narrower and the tape could move at a slower speed.c. The information was laid down as a series of slanted tracks.d. Recordings could be made and viewed at a later date. 29. Design change:All the improvements of VCRs.Result:a. The modern VCR could be produced. b. Far more data could be crammed into a smaller area.c. Recordings could be made and viewed at a later date.d. The rate at which the data could be stored or retrieved was increased.30. Early timers only switched the tape on at a certain time, leaving the VCR running until the tape finished.a. running until the tape finished is an adverb phrase.b. running until the tape finished is an adjective phrase. c. running until the tape finished is a noun phrase.d. running until the tape finished is a phrasal verb.

Unit 6 Digital watch1. Insteal of using the complicated springs, cogs, and wheels of a mechanical watch, the digital watch uses a vibrating __________ to keep time.a. Systemb. Crystal c. Ringd. Factor2. A digital watch is __________ to one second in 10 years.a. Accuratelyb. accurate c. accuracyd. accurateness3. The digital time display of a digital watch can be adjusted by __________a. Buttons b. Knobsc. a systemd. switches4. Which functions a typical digital watch can display?a. Time and day, a 12/24 hour option, a reminder, a stopwatch b. Time and day, an alarm, stopwatch, agendac. Time and day, a count down from 24 hours, work scheduled. Time and day, pictures, stopwatch, an alarm 5. The voltage applied to a quartz chip makes it expand and contract producing __________ a. Swingb. Powerc. Vibration d. motion 6. The power to make the quartz chip vibrate come from a battery which __________ at least one yeara. lasts b. expandsc. contractsd. dies7. Inside vacuum capsule, the quartz chip vibrates at a steady __________ of 32 768 vibrations a seconda. Frequency b. Vibratec. Vibrationd. status8. In a liquid crystal display, each pulse advances the display in one-second __________a. Intervals b. Lengthsc. Distancesd. status9. The traditional mechanical wristwatch uses a __________ and hairspring to keep timea. balance wheel b. balance systemc. switchd. electronic circuits10. In a digital watch mechanical parts have been replaced by a vibrating __________ controlled by minute electronic circuits.a. Systemb. quartz cystal c. equipmentd. matter11. One of the advantage of quartz in digital watches is that it is very __________a. Stablenessb. Stable c. easily seend. tiny12. The artificial quartz crystals used in digital watches are designed to vibrate up to 32,768 cycles per __________ when the current from a battery is passed through them.a. Second b. Minutec. Millisecondd. none of above answers is correct13. Each one second pulse triggers the microchip to send signals to digital display to advance the __________ by one second.a. Charactersb. Symbolsc. Lettersd. Numerals 14. Most modern quartz watches display the time in __________ on a liquid crystal display (LCD).a. Charactersb. Digits c. Lettersd. symbols15. They are used to control different functions of digital watches such as hour display, date and alarm signal. What are they?a. The pulses triggers the microchip to send signal to the digital display b. Vibrations of the quartz crystalsc. Batteriesd. Buttons16. LCD is a thin film of __________ which reacts to electrical charges placed between two sheets of glass.a. Waterb. Airc. Metald. liquid 17. A woltage is applyied to a quartz crystal making it expand and contract, producing vibration at a frequency of __________ per seconda. 32,768 b. 32,687c. 32,786d. 32,86718. The frequency which is created from quartz crytal is halved fifteen times by a microchip resulting in a frequency of one pulse per second.a. Fiftyb. Fivec. fifteen d. fourteen19. When the pulse is fed to __________ , it advances the display in one-second intervalsa. a quartz Crystalb. an LCD c. a digital watchd. a vacuum capsule20. The divider circuits in an electronics of a digital watch perform __________ division on the pulses to reduce frequency to one pulse per second.a. Decimalb. Sexagesimalc. Octald. Binary 21. The electronics of a digital watch may be contained in a single integrated circuit. This can be shown in a block diagram. Select the correct answer below to fill the empty rectanglesa. Oscillator counters dividers decodersb. Oscillator dividers counters decoders c. Dividers oscillator counters decodersd. Decoders counters dividers - oscillator22. They consist of circuits which switch between two stable states and rate known as bistables or flip-flops ( see figure below). What are they?a. They are countersb. They are decodersc. They are oscillatorsd. They are dividers 23. Each time a pulse is applied to the clock input of a flip-flop, its outputs change ther logic state from high (logic 1) to low ( logic 0 ) or vice versa. This means that two clock input pulses cause one pulse to be output from the flip-flop at output Q, as show in figure below: The flip-flop is acting as a binary frequency __________a. Divider b. Separatorc. Additiond. Multiplier24. The output of one flip-flop is connected to the input of the next, i.e. they are connected in __________ .a. Parallelb. Cascade c. Seriesd. darlington25. Oscillator is used for __________ a. producing signals to operate the LCDb. making a binary count of the pulsesc. displaying the timed. producing fixed frequency pulses 26. Divider is used for __________a. producing signals to operate the LCDb. making a binary count of the pulsesc. dividing the frequency 15 times d. producing fixed frequency pulses27. Counter is used for __________a. producing signals to operate the LCDb. making a binary count of the pulses c. displaying the timed. producing fixed frequency pulses28. Decoder is used for __________a. producing signals to operate the LCD b. making a binary count of the pulsesc. displaying the timed. producing fixed frequency pulses29. LCD is used for __________a. producing signals to operate the LCDb. making a binary count of the pulsesc. displaying the time d. producing fixed frequency pulses30. Older type telephone using rotor __________ , which generates pulses to code digits defining destinationa. Dialling b. Accessingc. Callingd. marking

Unit 7 Telecommunication1. __________ involves the transmission of information, including voice, data, TV, and radio over long distances.a. Televisionsb. Telecommunications c. Satellited. radio2. The transmission __________ can be free space (ground, space, and sky waves), or the information can be guided between transmitters and receivers using transmission line cables of various kinds.a. Equipmentb. Methodc. Wayd. Medium 3. __________ is the simplest type of transmission line consisting of a pair of sinsulated copper wires running side-by-side and covered by a plastic sheath.a. twisted pairb. coaxial cablec. parallel wires d. waveguides4. It is prone to interference and is only used to carry information over small distances such as telephone connections within a building. What is it?a. Parallel wires b. Waveguidesc. Coaxial cabled. Twisted pair5. Two insulated copper wires are twisted together to reduce interference effects and are enclosed in an insulating polyethylene sheath. What type of transmission line is this?a. Parallel wiresb. Waveguidesc. Coaxial cabled. Twisted pair 6. This is a type of transmission line which unwanted stray signals picked up by one tend to be cancelled by similar signals picked up by the other. What type of transmission line is this?a. Parallel wiresb. Waveguidesc. Twisted pair d. Coaxial cable7. __________ are used for communications to conncect telephones to their local exchange.a. Parallel wiresb. Waveguidesc. Coaxial cabled. Twisted pair 8. __________ has a copper wire core surrounded by copper braid. The core and braid are insulated from each other by a dielectric material such as polyethylene and covered by a PVC sheatha. Parallel wiresb. Waveguidesc. Coaxial cable d. Twisted pair9. The braid helps to screen the signals from __________ (see below figure)a. Dustb. Waterc. Aird. Interference 10. Coax can carry a large number of signals over long distances at frequencies up to __________a. 1000Mhz b. 10000Mhzc. 100000Mhzd. 1000000Mhz11. __________ is used to connect telephone exchanges and for cable televisiona. Parallel wiresb. Waveguidesc. Coax d. Twisted pair12. Microwaves can be guided along rectangular copper ducts by a series of reflections from the inner walls. What type of transmission is this?a. Parallel wiresb. Waveguides c. Coaxd. Twisted pair13. Waveguides are used to carry __________ signals between dish aerials and receivers.a. ultrasound waveb. sound wavec. microwave d. infrared rays14. See figure below. Which type of transmission does the figure describe?a. Parallel wiresb. Waveguidesc. Coaxial cable d. Optical fibres 15. Although the __________ has a smaller diameter than a human hair, it can be used to transmit ten of thousands of signals at high speed vith very low loss and no interference from other signals.a. parallel wiresb. optical fibres c. coaxial cabled. waveguides16. __________ cable can be used in corrosive environments and is light, flexible and cheap. It is gradually replacing conventional copper wire for connecting telephones and computer networks.a. Parallel wiresb. Coaxial cablec. Optical fibres d. Waveguides17. __________ , using the VHF band, were developed during the Second World War to provide communications for ships and aeroplanes.a. Radiophones b. Mobile phonesc. Telephonesd. Radar18. With mobile phone systems, all communications take place through a __________ .a. Cellb. cell clustersc. central control base station d. mobile units19. With mobile phone systems, mobile units normally __________ communicate __________ with other mobile unitsleave empty- directlya. leave empty - indirectlydo not directly b. do not - indirectly20. With mobile phone systems, mobile units __________ messages __________ the control base station and the base station controller relays the messages to other mobile units.a. send - to b. receive fromc. send fromd. receive to21. With mobile phone systems, although mobile phones can be moved, they must __________ fixed areas. This type of system is limited by the fact that there are not enough VHF frequencies available for large numbers of communication.a. be out ofb. stay within c. out ofd. within22. A cellular phone (cellphone) is a lightweight, portable radio __________ which can transmit and receive telephone calls anywhere in the cellular network area.a. Transceiver b. Transmitterc. Receiverd. medium23. In the cellular network area, the same __________ can be used for many different telephone calls at the same timea. Clusterb. Frequencies c. Aread. distance24. In the cellular network area, each communications area is divided into a number of hexagonal-shaped cells. Each cell is allocated a number of __________ for communications.a. frequency channels b. smaller cellsc. telephone linesd. units25. Although the frequencies used in any one cell __________ in its neighbouring cells, the same frequencies __________ in cells further away without causing interference.a. can be used are not usedb. are not used can be used c. are not used are also not usedd. can be used are used26. In the cellular network area, the size of the cells vary between 1 km to about __________ across.a. 30 km b. 45 kmc. 60 kmd. 75 km27. The variation of the size of the cells depends on the __________ of the cellphone transmitters.a. wave formb. speedc. output power d. location28. In communications area, each area can have a diffent number of cells, but a cluster of __________ cell give a good compromise between the number of frequency channels available in each cell and the interference between communications in differenct cells.a. Fiveb. Sixc. Seven d. eight29. In mobile networks, each cell has a small electronic __________ situated in a puplic place such as a car park or shopping centre.a. Controllerb. Unitc. Transmitterd. base station 30. In mobile networks, all the base stations for a cluster of cells are permanently connected to a __________ (MSC)a. Controllerb. main switching centre c. transmitterd. units

Unit 8 Cellphones1. In mobile networks, the MSC keeps a register of cellphones indicating their __________a. phone numberb. cell position c. calld. status2. If the cellphone moves to another cell, its new position is signalled to the __________a. main switching centre b. base stationc. public exchanged. unit3. When a call is made to a cellphone, the main switching centre first checks the registrations to find the __________ of the cellphonea. phone numberb. position c. calld. status4. In mobile networks, after the MSC checks the registrations, it then pages the cellphone and causes it to tune to the allocated __________ .a. Cellb. frequency channel c. positiond. status5. In mobile networks, the base station constantly monitors the __________ of a call.a. Cellb. frequency channelc. positiond. signal level 6. In mobile networks, if the signal level becomes too strong it will __________ to other users.a. cause interference b. transmit fasterc. transmit furtherd. transmit stronger7. In mobile networks, if the signal level becomes too weak, the MSC tests the __________ from neighbouring base stations and switches the call to another base station and speech channel if necessary.a. signal formb. position of the calc. signal strength d. power level8. When the MSC switches the call to another base station and speech channel. This may cause a period of silence of up to about __________ .a. 200 msb. 400 ms c. 600 msd. 800 ms9. The first true telecommunications systems using __________ to carry messages started in 1840s with machine telegraphy.a. electrical signals b. electromagnetic wavesc. Hertzian wavesd. energy10. Who is the first people developed the Morse Code?a. David Morseb. Samuel Morse c. Henry Morsed. Garry Morse11. The invention of the telephone enabled speech __________ transported as electrical signals along wires and revolutionized personal communicationsa. Isb. Wasc. Wered. To Be 12. In 1886, Hertz verified experimentally that electrical energy could be radiated and thus proved the existence of the __________ .a. electrical signalsb. electromagnetic waves c. Hertzian wavesd. energy13. In 1901, Marconi established long- distance telegraph communication by transmitting between __________a. France and USAb. France and USAc. England and Canada d. England and Russia14. Television was first established in __________a. 1937 b. 1927c. 1947d. 195715. __________ was developed from 1930s and played a vital role in aircraft detection and navigation in World War IIa. Radar b. Radioc. TVd. Telephony16. The transistor was invented in __________a. 1937b. 1927c. 1947 d. 195717. Data communications the transmission of coded data between intelligent terminals and computers was first established in the early __________ .a. 1960sb. 1930sc. 1950s d. 1940s18. A document can be sent from one fax machine to another via __________ .a. telephone line b. fibre cablec. internetd. All of above are not correct19. A document is fed into the fax machine, it passes over a __________ which bounces light off the paper, reflecting the image on to a lensa. fluorescent tube - paperb. fluorescent tube lens c. plastic tube paperd. plastic tube lens20. In fax machines, the lens passes the light on to a __________ which breaks the image down to a series of __________ .a. microprocessor vertical linesb. paper horizontal linesc. paper dotd. microprocessor horizontal lines 21. In fax machines, a microprocessor converts each line to a series of black and white dots, which are then coded, usually as 0 for black and 1 for white ( binary code). This is turn converted into digital information.Where does the operation happen?a. At the receving fax machineb. At the sending fax machine c. On the telephone lined. All of above are not correct22. In fax machines, a third microprocessor(or modem) converts digital information into signals, called analogue tones, which can be sent down telephone lines. Where does the operation happen?a. At the receving fax machineb. At the sending fax machine c. On the telephone lined. All of above are not correct23. In fax machines, the analogue tones are converted back into binary signals and fed into a thermal head Where does the operation happen?a. At the receving fax machine b. At the receving fax machinec. On the telephone lined. All of above are not correct24. In fax machines, a microprocessor converts each line to a series of black and white dots, which are then coded, usually as 0 for black and 1 for white ( binary code). This is turn converted into digital information.a. This is decoding phaseb. This is coding phase c. This is tranferring phased. This is receving phase25. In fax machines, the analogue tones are converted back into binary signals and fed into a thermal head.a. This is decoding phase b. This is coding phasec. This is tranferring phased. Not identify26. In fax machines, the __________ is a mechanism containing a line of dots which heat up or cool down depending on the electrical current supplied to them by the binary code.a. Devicesb. Lensc. fluorescent tubed. thermal head 27. Facsimile machines only came into widespread use in the __________ when international standards were set by CCITT, a body based in France.a. late 1970s b. late 1960sc. late 1750sd. late 1980s28. The lastest machines, which must be linked to a special __________ , can send a document to several places at once for the price of one phone call.a. analog phone lineb. digital phone line c. fibre cabled. parallel cable29. Facsimile transmission involves __________ a document along a telephone line and converting the received signals into a reproduction of the original.a. Receivingb. Readingc. Sending d. bringing30. __________ can now send an A4 document, containing images as well as words, in less than a minute.a. Photocopy machinesb. Scanning machinesc. Printing machinesd. Fax machines