Transmission Lines 1.
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When tthe When he ttra rans nsmi miss ssio ionn line line is is matc matche hedd to the load, it a. Tran Transf sfer erss max maxim imum um curr current ent to the the load b. Tran Transf sfer erss max maxim imum um volt voltag agee to to the the load c. Trans ransfe fers rs maxi maximu mum m powe powerr to the the load d. Redu Reducces the load oad cur curre rent nt
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When mism When mismat atch ch is grea great, t, this this powe powerr actuall$ cause damage to the transmitter or the line itself. a. The incident power b. The reflected power c. The power dissipation d. The carrier power
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The meas measur uree ooff the the super superio iori rit$ t$ of a material over vacuum as a path for magnetic lines of force is a. ermitivit$ b. Permeability c. onductivit$ d. Resistivit$
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coax coax lin linee has has an an aatte ttenu nuat atio ionn of 2.( 2.( dd* * per 1'' ft. The attenuation for 2.0& ft. is ____ d*. a. 2.( b. (. c. #.# d. 6.6
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The char charac acte teri rist stic ic impe impeda danc ncee ooff a transmission line is determined b$ a. Its length b. 4ts 4ts hhei eigh ghtt abo abovve ggro roun undd c. 4ts 4ts ph$s ph$sic ical al cons constr truc uctition on d. The The oopperat eratiing fre fre%u %ueenc$ nc$
To ccoup ouple le a ccoax oaxial ial line line to a ppara aralle llell wire wire line, it is best to use a _____ a. lotted line b. !ire !irecction tional al coupl oupler er c . B a lu n d. "uar "uarte terr wave wavellengt engthh tran transf sfor orme merr To be prop proper erl$ l$ matc matche hed, d, the the ratio ratio of maximum to minimum voltage along a transmission line should be e%ual to a. &' b. 1' c. 2 d. 1 )or )or tran transm smis issi sion on lin linee load load mat match chin ingg over over a range of fre%uencies, it is best to use a a. *alun b. *roa *roadb dban andd dire direct ctio iona nall coup couple lerr c. Double stub d. ing inglle aadd+us +ustabl tablee ssttub
1'. onsidering onsidering a coaxial coaxial transmiss transmission ion line, maximum voltage on the line divided b$ the minimum voltage e%uals the a. har harac acte teri rist stic ic 4mpe 4mpeda danc ncee b. 4WR c. !"# d. 4ndu 4nduct ctiive Reac Reacttanc ance
The The prop propert ert$$ of a mate materi rial al ttha hatt dete determ rmin ines es how much electrostatic energ$ can be stored per unit volume when voltage is applied. a. ermeabilit$ b. -agnetic eefffect c. apacitance d. Permittivity
11. Transmis Transmission sion lines lines are are either either balanced balanced or unbalanced with respect to a. 5ega egative terminal b. 4nput 1
Transmission Lines c. d.
$round ositive terminal
10. Reflections on a transmission line can occur when
12. The radiation resistance of a %uarter wave antenna is a. (3 ohms b. 2 ohms c. %& ohms d. 1(( ohms
a. 4mpedance of the source and load are matched b. Impedance of the source and the load are mismatched c. Resonance conditions are obtained d. ower transfer between source and load is maximum
1#. The 6WR for a line terminated in its 7o is a. ' b. 1 c. 1.& d. 4nfinit$
1. measure of the mismatch between line and load impedance is called as a. Reflection coefficient b. !tanding wave ratio c. Loss d. tanding waves
1(. 0&8+&' ohm load is connected to a coaxial transmission line of 7' 9 0& ohms at 1':;<. The best method of matching consists in connecting a. short8circuited stub at the load b. capacitance at some specific distance from the load c. n inductance at the load d. ' short(circuited stub at some specific distance from the load
13. t matched condition, WR is e%ual to a. 7ero b. *ne c. 1'' d. 4nfinite
1&. resultant wave due to the combination of incident and reflected wave. a. =lectromagnetic wave b. ine wave c. !tanding wave d. urrent
2'. characteristic of an infinite transmission line is that a. The impedance in e+uals impedance out b. 4t carries waves at the velocit$ of light c. 4t can be connected to mismatched loads d. The impedance varies with the length of the line
1/. 4f the load impedance matches the characteristic impedance of the line, there are __________ standing waves. a. -ore b. Less c. )o d. Ten >1'?
21. The outer conductor of a coaxial transmission line is usuall$ grounded at the@ a. Input and output 2
Transmission Lines b. Autput onl$ c. 4nput onl$ d. oint of infinite resistance
2/. The characteristic impedance of a transmission line does not depend upon its a. Length b. onductor diameter c. onductor spacing d. Thic/ness of armor
22. 4f the input impedance of an antenna is #'' ohms and it is fed with a /'' ohm balanced transmission line, the WR on the line is a. ( b. # c. & d. '.&
20. 4t is re%uired to match a 0#8ohm antenna to a /'' ohm pol$eth$lene coaxial feeder line, with a velocit$ factor of '.// b$ means of a %uarter wave matching transformer. t a fre%uenc$ of 1&' -;<, the impedance of the matching section is ________ ohms. a. &0.& b. #1'.& c. 1&'.2 d. (&'.2
2#. The ratio of the reflected voltage to the incident voltage on the transmission line is termed as a. #eflection coefficient b. tanding wave ratio c. Loss d. tanding waves
2. The characteristic impedance of a transmission line is the impedance measured at the _____ when its length is infinite. a. horted end of the line b. -idsection c. Input d. Autput
2(. Termination means a. ,oad connected to the output end of a transmission line b. Result of disconnecting a line from a transmitter c. LooBing bacB impedance of a line with no load d. Result of cutting both ends of a conductor
23. 4t is re%uired to match a 2'' ohm load to a #'' ohm transmission line to reduce the WR and attain resonance. %uarter wave transformer used, directl$ connected to the load has a 7o of ______ ohms. a. &2- b. (2& c. &2( d. 2&(
2&. ermeabilit$ is the measure of superiorit$ of a material over vacuum as a path of magnetic lines of force. The permeabilit$ of free space is e%ual to ______ henr$Cmeter a. 1.&-% x 1exp(6 b. 1.&20 x 1'exp D/ c. 0.2&1 x 1'exp8/ d. &.210 x 1'exp8/
#'. The mismatch between antenna and transmission line impedances cannot be corrected b$ #
Transmission Lines a. b. c. d.
Esing an L networB d+usting antenna length 3sing a balun d+usting the length of the transmission line
c. d.
#1. The most desirable value of WR on a transmission line is a. ' b. 1 c. 2 d. 4nfinit$ #2. t ver$ high fre%uencies, transmission lines are used as ________ a. Tuned circuits b. ntennas c. 4nsulators d. Resistors
capacitance at some specific distance from the load ' short(circuited stub at some specific distance from the load
#/. What is the characteristic impedance of a single wire with diameter d 9 '.2& mm placed at the center between grounded parallel planes separated b$ 1 mm apart. The wire is held b$ a material with a velocit$ factor of '.0&. a. & ohms b. /# ohms c. &' ohms d. %- ohms
##. The minimum voltage along a transmission line is 2/' volts, while the maximum is #3' volts. The WR is a. './0 b. 1.' c. 1.2 d. 1.-
#0. Referred to the dielectric constant of a transmission line material a. 4nductance and capacitance b. elocity factor c. haracteristic impedance d. ropagation velocit$
#(. What characteristic impedance is needed to match a &'8ohm line to a #'' ohm8 loadF a. 221 ohms b. 1&& ohms c. 212 ohms d. 112 ohms
#. To couple a coaxial line to a parallel8wire line, it is best to use a a. lotted line b. Balun c. !irectional coupler d. "uarter8wave transformer
#&. >0& D +&'? 8Ω load is connected to a coaxial transmission line of 7 o 9 0& Ω, at 1' :;<. The best method of matching consists in connecting a. short8circuited stub at the load b. n inductance at the load
#3. Transmission line consisting of two conductors that have e%ual resistance per unit length.
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Transmission Lines a. Enbalanced line b. Apen8wire line c. Balanced line d. oaxial line
c. apacitor d. 4nductor ((. t E;) and microwave fre%uencies, transmission lines are commonl$ used as a. ntenna b. oupler c. #esonant circuit d. Transformer
('. )or maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line 7o and the load impedance 7l should be 4 o 5 4 , '. 7o G 7L B. 7o H 7L . 7o 9 ' D.
(&. Transmission line is a two8wire cable that connects the transmitter to the antenna or the antenna to the receiver. The purpose of the transmission line is to a. mplif$ the R) signal b. -odulate the signal c. arry the #7 energy for the desired distance d. ll of the above
(1. 4n the stud$ of transmission cable, twin lead is also referred to as a __________. a. Twisted pair b. !ouble cable c. #ibbon cable d. Apen pair
(/. To prevent radiation losses and interference from external sources, the inner conductor of this transmission line is completel$ enclosed with a metal sheath or braid. a. oaxial cable b. Apen8wire transmission lines c. Aptical cables d. Waveguides
(2. ratio expressing the percentage of incident voltage reflected on a transmission line is Bnown as the a. 6elocit$ factor b. tanding8wave ratio c. #eflection coefficient d. Line efficienc$ (#. n open %uarter8wave line at the operating fre%uenc$ acts liBe a>n? a. !eries resonant circuit b. arallel resonant circuit
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Transmission Lines (0. The characteristic impedance of a transmission line is determined b$@ a. 4ts operating fre%uenc$ b. 4ts length c. Its physical si8e and arrangement d. The signal applied at the input terminal (. hunt capacitance was determined due to@ a. onductors were closed to each other b. The length and diameter of the conductors c. !ielectric losses d. )lux linBages (3. t radio fre%uencies, a line is considered lossless because@ a. haracteristic impedance is determined b$ its ph$sical structure b. 4nductive reactance is much more than the resistance c. apacitive reactance is much larger than the shunt conductance d. Both B and &'. 4f a change in the dielectric material decreases the capacitance, the characteristic impedance is a. Iept constant b. c. d.
!ecreased Increased halved /
