89 + Interview Questions in Waveguides in Electromagnetic Theory Page 1 InterviewSolution

1.	The number of modes in a waveguide having a V number of 10 is(a) 10(b) 25(c) 100(d) 50I got this question in class test.Query is from Transverse Electric Waves(TE) topic in division Waveguides of Electromagnetic Theory
Answer» The CORRECT answer is (d) 50 Explanation: The NUMBER of modes is given by m = V^2/2, where V is the v number. On SUBSTITUTING for V = 10, we get m = 100/2 = 50.

Discussion

2.	The scattering parameters are used to indicate the(a) Permittivity and permeability(b) Electric and magnetic field intensities(c) Reflection and transmission coefficients(d) Frequency and wavelengthThe question was asked in my homework.This key question is from Types of Waveguides in division Waveguides of Electromagnetic Theory
Answer» Right CHOICE is (c) Reflection and transmission coefficients The explanation is: The SCATTERING matrix consists of the transmission coefficients in the main DIAGONAL and the reflection coefficients in the opposite diagonal.

Discussion

3.	The circular waveguides use which function in the frequency calculation?(a) Laplace function(b) Schottky function(c) Bessel function(d) Transfer functionI got this question by my school teacher while I was bunking the class.I want to ask this question from Types of Waveguides topic in chapter Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (C) Bessel function The best I can explain: The circular or cylindrical waveguides USE the Bessel function for the frequency calculation of a PARTICULAR mode.

Discussion

4.	The dominant mode in rectangular waveguide is(a) TE01(b) TE10(c) TM01(d) TM10I got this question during an interview.Origin of the question is Transverse Electric Waves(TE) in chapter Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (b) TE10 To elaborate: TE10 is the DOMINANT mode in the rectangular WAVEGUIDE. This is because it gives the minimum cut off frequency required for transmission.

Discussion

5.	The exciter of the waveguide in a transmission line is the(a) Transmitter(b) Receiver(c) Transponder(d) AntennaThis question was addressed to me at a job interview.My question is taken from Transients topic in portion Waveguides of Electromagnetic Theory
Answer» Right answer is (d) ANTENNA To elaborate: The waveguide is usually excited by the antenna ROD. The REFLECTION depends on the PHASE of EXCITATION and the antenna current.

Discussion

6.	The phase of the wave after the installation of the guided terminations will be(a) 0(b) 45(c) 90(d) 180The question was asked by my school teacher while I was bunking the class.My question is taken from Transients in chapter Waveguides of Electromagnetic Theory
Answer» The CORRECT answer is (a) 0 To elaborate: Using a guided termination, the guides serves as a reflector. If the distance between the EXCITER and the wall is properly ADJUSTED, the transmitted and the reflected WAVE will be in phase.

Discussion

7.	The form or mode of propagation is determined by which factors?(a) Type of excitation device(b) Location of excitation device(c) Type and location of the excitation device(d) Waveguide characteristicsI have been asked this question during an online interview.My question is taken from Transients in division Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (C) Type and location of the excitation DEVICE The best EXPLANATION: The form and the mode of PROPAGATION of the wave in a waveguide is determined by the type and location of the excitation device.

Discussion

8.	The power of a wave having an electric field strength of 12.8 units is(a) 0.217(b) 0.721(c) 0.127(d) 0.172I have been asked this question during a job interview.This intriguing question originated from Transients in chapter Waveguides of Electromagnetic Theory
Answer» Correct ANSWER is (a) 0.217 Best explanation: The power of a wave is given by P = 0.5 E^2/η, where E is the ELECTRIC field intensity and η is the intrinsic IMPEDANCE. On SUBSTITUTING for E = 12.8 and η = 377, we get P = 0.5 x 12.8^2/377 = 0.217 units.

Discussion

9.	The power of a wave having a magnetic field intensity of 2.5 units is(a) 1.17 kilo watt(b) 1.17 mega watt(c) 1.17 watt(d) 11.7 wattI had been asked this question during an interview.My question comes from Transients in division Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (a) 1.17 kilo watt The explanation: The POWER of a wave is given by P = 0.5 η H^2, where η is the intrinsic IMPEDANCE and H is the magnetic field INTENSITY. On substituting for η = 377 and H = 2.5, we GET P = 0.5 x 377 x 2.5^2 = 1.17 kilo watts.

Discussion

10.	The power of a wave in a transmission line, when the current and the resistance are 5A and 120 ohm respectively is(a) 3000(b) 4000(c) 2000(d) 1500The question was asked in quiz.Enquiry is from Transients topic in section Waveguides of Electromagnetic Theory
Answer» Correct OPTION is (a) 3000 Easy EXPLANATION: The power of a line is given by P = I^2R. On SUBSTITUTING for I = 5 and R = 120, we get P = 5^2 x 120 = 3000 units.

Discussion

11.	The cut off frequency of a waveguide with resonant cavity is given by(a) V√((m/a)^2 + (n/b)^2 + (p/d)^2)/2(b) V√((m/a)^2 + (n/b)^2 + (p/d)^2)(c) 2V√((m/a)^2 + (n/b)^2 + (p/d)^2)(d) V√((m/a) + (n/b) + (p/d))/2I have been asked this question in an interview.This intriguing question comes from Transients in division Waveguides of Electromagnetic Theory
Answer» Right option is (a) V√((m/a)^2 + (n/b)^2 + (p/d)^2)/2 The BEST explanation: The cut off FREQUENCY of the waveguide of DIMENSIONS a x b with the resonant CAVITY of dimension d is GIVEN by fc = √((m/a)^2 + (n/b)^2 + (p/d)^2)/2. Here m and n are the orders of the waveguide, p is the order of the cavity and v is the velocity.

Discussion

12.	When a waveguide is terminated, the mode of the guided termination will be(a) zero(b) non-zero(c) infinite(d) does not existI have been asked this question in an international level competition.I need to ask this question from Transients topic in section Waveguides of Electromagnetic Theory
Answer» Right ANSWER is (b) non-zero Easy explanation: A waveguide mode with a guided TERMINATION is represented by TEmnp and TMmnp. Here m and N are the orders of the waveguide and p is the ORDER of the resonant cavity. It is always a non-zero value.

Discussion

13.	The resonant circuit in a waveguide refers to the(a) Tank circuit(b) RC circuit(c) Bridge circuit(d) Attenuator circuitThe question was asked in final exam.This is a very interesting question from Transients in division Waveguides of Electromagnetic Theory
Answer» Right option is (a) Tank circuit Easy EXPLANATION: The RESONANT circuit REFERS to the tank circuit. It is parallel combination of an INDUCTOR and a capacitor.

Discussion

14.	Cavity wave meters are used to measure which parameter of the wave?(a) Wavelength(b) Reflection factor(c) Phase(d) FrequencyThis question was posed to me during an interview.This interesting question is from Waveguide Current and Excitation in division Waveguides of Electromagnetic Theory
Answer» Correct CHOICE is (d) FREQUENCY Explanation: Cavity resonators are USED in cavity wave meters for the measurement of frequency of the MICROWAVE SIGNALS.

Discussion

15.	One of the applications of the cavity resonators is duplexer in RADAR systems. State true/false.(a) True(b) FalseThis question was posed to me in an interview for job.The above asked question is from Waveguide Current and Excitation topic in portion Waveguides of Electromagnetic Theory
Answer» The correct choice is (a) True To elaborate: CAVITY resonator is used in duplexers of RADAR systems, as RESONANT cavity in transmit RECEIVE (TR) tubes and antitransmit receive (ART) tubes.

Discussion

16.	The cavity resonators used in the reflex klystron oscillators are for(a) Generating RF signals(b) Generating microwave signals(c) Amplifying RF signals(d) Amplifying microwave signalsI have been asked this question by my school principal while I was bunking the class.This intriguing question originated from Waveguide Current and Excitation topic in division Waveguides of Electromagnetic Theory
Answer» Right OPTION is (b) Generating microwave SIGNALS The EXPLANATION is: OSCILLATORS are devices that GENERATE signal waveforms. The reflex klystron oscillator is used to generate microwave signals.

Discussion

17.	The cavity resonators are used in the klystron amplifiers for(a) Amplifying RF signals(b) Amplifying microwave signals(c) Attenuating RF signals(d) Attenuating microwave signalsThe question was asked by my school principal while I was bunking the class.The question is from Waveguide Current and Excitation topic in section Waveguides of Electromagnetic Theory
Answer» Right choice is (B) Amplifying MICROWAVE SIGNALS The explanation: The CAVITY resonators are employed in the KLYSTRON amplifiers for amplifying the microwave signals.

Discussion

18.	For efficient transmission, the characteristic impedance of the transmission line has to be(a) 50 ohm(b) 75 ohm(c) Either 50 or 75 ohm(d) Neither 50 nor 75 ohmI have been asked this question during an interview.Origin of the question is Waveguide Current and Excitation in portion Waveguides of Electromagnetic Theory
Answer» CORRECT answer is (C) Either 50 or 75 ohm For explanation: Generally, for IDEAL transmission lines, the characteristic impedance should be either 50 ohm or 75 ohm.

Discussion

19.	Which of the following parameter cannot be calculated from the standing waves?(a) Peak voltage and peak current(b) SWR(c) Reflection and transmission coefficients(d) Attenuation constantThe question was posed to me during a job interview.This is a very interesting question from Waveguide Current and Excitation topic in portion Waveguides of Electromagnetic Theory
Answer» Right choice is (d) Attenuation constant Easiest explanation: The peak voltage and current can be DIRECTLY measured from the standing WAVES. The standing wave ratio, reflection coefficient and the TRANSMISSION coefficient can also be calculated from it. Only the attenuation constant cannot be calculated directly.

Discussion

20.	Which type of wave does the resonant cavity produce?(a) Standing waves(b) Guided waves(c) Transmitted waves(d) Attenuated wavesThis question was posed to me in an online quiz.My question is based upon Waveguide Current and Excitation in division Waveguides of Electromagnetic Theory
Answer» The correct option is (a) Standing WAVES The EXPLANATION is: RESONANT CAVITY is the waveguide shorted by a conducting PLATE. This is to reduce the reflection losses. Such arrangement leads to standing waves.

Discussion

21.	The guided terminations are used to(a) Increase reflection(b) Increase transmission(c) Eliminate reflection loss(d) Eliminate attenuationThe question was posed to me during an interview.This is a very interesting question from Waveguide Current and Excitation in section Waveguides of Electromagnetic Theory
Answer» RIGHT choice is (C) Eliminate reflection loss Easy EXPLANATION: The guided termination refers to the waveguide SHORTED by conducting plates. This is done in order to eliminate the reflection losses.

Discussion

22.	The source voltage of a 75ohm transmission line is given by 150V. Find the load current.(a) 0.5(b) 2(c) 4(d) 1This question was posed to me in exam.Enquiry is from Waveguide Current and Excitation topic in portion Waveguides of Electromagnetic Theory
Answer» CORRECT answer is (b) 2 To explain: The LOAD current is given by IL = VS/Z0. On substituting for VS = 150 and Z0 = 75, we get IL = 150/75= 2A.

Discussion

23.	The phase and group velocities does not depend on which of the following?(a) Frequency(b) Wavelength(c) Phase constant(d) Attenuation constantThis question was posed to me in a job interview.My doubt is from Phase and Group Velocity topic in section Waveguides of Electromagnetic Theory
Answer» Right option is (d) ATTENUATION CONSTANT Easiest explanation: The phase and the group velocities are directly RELATED by the frequency, WAVELENGTH and the phase constant. It is INDEPENDENT of the attenuation constant.

Discussion

24.	The phase velocity of a wave having a phase constant of 4 units and a frequency of 2.5 x 10^9 radian/sec is (in 10^8 order)(a) 3.25(b) 3.75(c) 6.25(d) 6.75The question was posed to me during a job interview.This is a very interesting question from Phase and Group Velocity in section Waveguides of Electromagnetic Theory
Answer» RIGHT OPTION is (c) 6.25 The explanation is: The PHASE velocity and the phase constant are related by VP = ω/βg. On substituting for ω = 2.5 x 10^9 and β = 4, we get the phase velocity as 6.25 units.

Discussion

25.	The phase velocity refers to a group of waves and the group velocity refers to a single wave. State true/false.(a) True(b) FalseThe question was posed to me in my homework.The question is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory
Answer» RIGHT option is (B) False Easy EXPLANATION: The phase VELOCITY refers to a single wave and the GROUP velocity refers to a group of waves.

Discussion

26.	The guided wavelength and the phase constant are related by(a) 2π/βg = λg(b) 1/βg = λg(c) 1/2πβg = λg(d) βg = λgThis question was addressed to me during an internship interview.My query is from Phase and Group Velocity topic in division Waveguides of Electromagnetic Theory
Answer» The correct choice is (a) 2π/βg = λg Best EXPLANATION: The GUIDED WAVELENGTH and the phase constant are RELATED by 2π/βg = λg, where βg is the guided phase constant and λg is the guided wavelength.

Discussion

27.	The group velocity of a wave with a phase velocity of 60 x 10^9 is (in 10^6 order)(a) 1.5(b) 2(c) 2.5(d) 3I had been asked this question in a national level competition.This question is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (a) 1.5 The explanation: We know that the phase and the group velocities are given by Vp X Vg = c^2. On SUBSTITUTING for Vp = 60 x 10^9 and the speed of light, we GET Vg = 1.5 x 10^6 m/s.

Discussion

28.	The phase velocity of a wave having a group velocity of 6 x 10^6 is (in order of 10^8 m/s)(a) 2.4(b) 3(c) 15(d) 150This question was addressed to me by my college professor while I was bunking the class.This question is from Phase and Group Velocity topic in chapter Waveguides of Electromagnetic Theory
Answer» The correct OPTION is (d) 150 For EXPLANATION: We KNOW that the phase and the group velocities are GIVEN by Vp x Vg = c^2. On SUBSTITUTING for Vg = 6 x 10^6 and the speed of light, we get Vp = 150 x 10^8 m/s.

Discussion

29.	The cut off wavelength of the rectangular waveguide in dominant mode with dimensions 6 cm x 4 cm is(a) 12cm(b) 6cm(c) 4cm(d) 2cmThe question was posed to me in semester exam.I'm obligated to ask this question of Phase and Group Velocity topic in portion Waveguides of Electromagnetic Theory
Answer» Correct OPTION is (a) 12cm Best explanation: The cut off WAVELENGTH in the DOMINANT mode is given by λc = 2a/m, where a is the broad wall dimension. On substituting for m = 1 and a = 6CM, we get the cut off wavelength as 12cm.

Discussion

30.	The product of the phase and the group velocities is given by the(a) Speed of light(b) Speed of light/2(c) 2 x Speed of light(d) (speed of light)/4The question was posed to me during an internship interview.Query is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory
Answer» Correct choice is (d) (speed of light)/4 Best EXPLANATION: The product of the phase and the GROUP VELOCITIES is given by the square of the speed of the light. THUS Vp X Vg = c^2 is the relation.

Discussion

31.	The cut off wavelength and the guided wavelength are given by 0.5 and 2 units respectively. Find the wavelength of the wave.(a) 0.48(b) 0.32(c) 0.45(d) 0.54I got this question in an interview.This key question is from Phase and Group Velocity in chapter Waveguides of Electromagnetic Theory
Answer» The correct option is (a) 0.48 Best EXPLANATION: The cut off wavelength and the GUIDED wavelength are related as (1/λ)^2 = (1/λc)^2 + (1/λg)^2. On SUBSTITUTING for λc = 0.5 and λg = 2, we get λ = 0.48 units.

Discussion

32.	The term cos θ is given by 2.5. Find the phase velocity.(a) 3(b) 5(c) 7.5(d) 2.5I have been asked this question in quiz.I would like to ask this question from Phase and Group Velocity in division Waveguides of Electromagnetic Theory
Answer» CORRECT CHOICE is (c) 7.5 For EXPLANATION I would say: The phase VELOCITY is given by VP = c cos θ. On substituting for cos θ = 2.5 and the speed of light, we get the phase velocity as 7.5 x 10^8 m/s.

Discussion

33.	In a waveguide, which of the following condition is true always?(a) phase velocity = c(b) group velocity = c(c) phase velocity > c(d) phase velocity < cThis question was addressed to me during an interview for a job.My doubt stems from Phase and Group Velocity topic in division Waveguides of Electromagnetic Theory
Answer» RIGHT option is (c) PHASE velocity > c Explanation: The phase velocity is always GREATER than the speed of light in WAVEGUIDES. This IMPLIES the group velocity is small.

Discussion

34.	For a TEM wave to propagate in a medium, the medium has to be(a) Air(b) Insulator(c) Dispersive(d) Non dispersiveThis question was posed to me in semester exam.Question is taken from Transverse Electric Magnetic Waves(TEM) in portion Waveguides of Electromagnetic Theory
Answer» The correct answer is (d) Non dispersive Best explanation: The medium in which the TEM waves propagate has to be non- dispersive. This implies the phase VELOCITY and the characteristic impedance has to be constant over a WIDE BAND.

Discussion

35.	Which type of transmission line accepts the TEM wave?(a) Copper cables(b) Coaxial cable(c) Rectangular waveguides(d) Circular waveguidesI have been asked this question at a job interview.This is a very interesting question from Transverse Electric Magnetic Waves(TEM) in chapter Waveguides of Electromagnetic Theory
Answer» RIGHT OPTION is (b) Coaxial cable Explanation: Hollow TRANSMISSION lines support TE and TM waves only. The TEM wave is possible only in the coaxial cable transmission line, which is not hollow.

Discussion

36.	The guided phase constant of a TEM wave in a waveguide with a phase constant of 2.8 units is(a) 2.8(b) 1.4(c) 0(d) InfinityThe question was posed to me in an interview for internship.My question comes from Transverse Electric Magnetic Waves(TEM) in chapter Waveguides of Electromagnetic Theory
Answer» The CORRECT OPTION is (a) 2.8 Easiest explanation: The guided phase constant is same as the phase constant of the waveguide. For the GIVEN DATA, the guided phase constant is 2.8 units.

Discussion

37.	The guided wavelength of a TEM wave in a waveguide having a wavelength of 5 units is(a) 0(b) Infinity(c) 5(d) 1/5I have been asked this question in examination.Question is taken from Transverse Electric Magnetic Waves(TEM) in portion Waveguides of Electromagnetic Theory
Answer» Right choice is (c) 5 Easy explanation: The GUIDED wavelength is same as the wavelength of the waveguide with a TEM WAVE. THUS the guided wavelength is 5 units.

Discussion

38.	The cut off wavelength in the TEM wave will be(a) 0(b) Negative(c) Infinity(d) 1/6 GHzI got this question in final exam.This key question is from Transverse Electric Magnetic Waves(TEM) topic in section Waveguides of Electromagnetic Theory
Answer» The correct OPTION is (C) Infinity Explanation: The cut off frequency in a TEM WAVE is zero. THUS the cut off wavelength will be infinity.

Discussion

39.	TEM wave can propagate in rectangular waveguides. State true/false.(a) True(b) FalseThis question was posed to me in exam.This intriguing question comes from Transverse Electric Magnetic Waves(TEM) topic in portion Waveguides of Electromagnetic Theory
Answer» Right option is (b) False Easy explanation: The rectangular waveguide does not allow the TEM wave. TEM MODE can exist only in two CONDUCTOR system and not in HOLLOW waveguide in which the centre conductor does not exist.

Discussion

40.	Which component is non zero in a TEM wave?(a) Ex(b) Hz(c) Ez(d) Attenuation constantThis question was posed to me by my school principal while I was bunking the class.I'm obligated to ask this question of Transverse Electric Magnetic Waves(TEM) topic in chapter Waveguides of Electromagnetic Theory
Answer» The CORRECT option is (a) EX To elaborate: In a TEM wave, the wave propagates along the GUIDED axis. Thus the COMPONENTS Ez and HZ are zero. The attenuation is also zero. The non-zero component will be Ex.

Discussion

41.	The cut off frequency of the TEM wave is(a) 0(b) 1 GHz(c) 6 GHz(d) infinityI had been asked this question in a job interview.I want to ask this question from Transverse Electric Magnetic Waves(TEM) in chapter Waveguides of Electromagnetic Theory
Answer» Right option is (a) 0 The best I can explain: The TEM waves have both E and H PERPENDICULAR to the GUIDE axis. Thus its cut off FREQUENCY is zero.

Discussion

42.	In a transverse electric magnetic wave, which of the following will be true?(a) E is transverse to H(b) E is transverse to wave direction(c) H is transverse to wave direction(d) E and H are transverse to wave directionThe question was asked in semester exam.I'm obligated to ask this question of Transverse Electric Magnetic Waves(TEM) in division Waveguides of Electromagnetic Theory
Answer» The CORRECT answer is (d) E and H are TRANSVERSE to wave direction The BEST I can explain: In the transverse electric magnetic wave (TEM wave), both the electric and magnetic FIELD strengths are transverse to the wave propagation.

Discussion

43.	The distance between two terminated plates is given by the(a) Guided wavelength(b) 2(guided wavelength)(c) Guided wavelength/2(d) (Guided wavelength)/4The question was posed to me by my school principal while I was bunking the class.The query is from Transverse Magnetic Waves(TM) topic in section Waveguides of Electromagnetic Theory
Answer» CORRECT answer is (c) Guided WAVELENGTH/2 Explanation: The DISTANCE between the terminating plates is given by VMIN = λg/2, where λg is the guided wavelength.

Discussion

44.	The reflection coefficient, when a resonant cavity is placed between the waveguide is(a) 0(b) 1(c) -1(d) InfiniteI had been asked this question in an international level competition.Origin of the question is Transverse Magnetic Waves(TM) in division Waveguides of Electromagnetic Theory
Answer» Right choice is (B) 1 Best explanation: When the waveguide is shorted by conducting PLATES, the REFLECTION coefficient will be unity. This will LEAD to the OCCURRENCE of standing waves.

Discussion

45.	The boundary between the Fresnel and Fraunhofer zones having a length of 12 units and a wavelength of 3 units is(a) 96(b) 48(c) 192(d) 36The question was asked by my college professor while I was bunking the class.This intriguing question originated from Transverse Magnetic Waves(TM) in division Waveguides of Electromagnetic Theory
Answer» RIGHT answer is (a) 96 The explanation: The Fresnel- Fraunhofer boundary is related by the wavelength as R = 2L^2/λ. On SUBSTITUTING for L = 12 and λ = 3, we get R = 2 X 12^2/3 = 96 units.

Discussion

46.	Does the mode TM30 exists?(a) Yes(b) NoI got this question in an international level competition.Asked question is from Transverse Magnetic Waves(TM) in portion Waveguides of Electromagnetic Theory
Answer» The correct answer is (B) No To EXPLAIN: Modes in the format of TMmo and TMon does not EXIST. The given mode is in the form of TMmo, which is does not exist. It is an evanescent mode.

Discussion

47.	Two modes with same cut off frequency are said to be(a) Generate modes(b) Dominant modes(c) Degenerate modes(d) Regenerate modesI got this question in a national level competition.I want to ask this question from Transverse Magnetic Waves(TM) topic in chapter Waveguides of Electromagnetic Theory
Answer» CORRECT choice is (c) DEGENERATE modes The BEST I can EXPLAIN: Two modes with same cut off frequency are called as degenerate modes. These modes have same field DISTRIBUTION.

Discussion

48.	The modes TMmo and TMon are called(a) Generate modes(b) Degenerate modes(c) Dominant modes(d) Evanescent modesI have been asked this question by my college director while I was bunking the class.Origin of the question is Transverse Magnetic Waves(TM) topic in chapter Waveguides of Electromagnetic Theory
Answer» The correct answer is (d) EVANESCENT modes Best EXPLANATION: The modes TMMO and TMon does not EXIST. These modes are said to be evanescent mode.

Discussion

49.	The intrinsic impedance of a TM wave will be(a) Greater than 377 ohm(b) Equal to 377 ohm(c) Lesser than 377 ohm(d) Does not existThe question was posed to me in semester exam.My question is taken from Transverse Magnetic Waves(TM) in portion Waveguides of Electromagnetic Theory
Answer» RIGHT OPTION is (c) Lesser than 377 ohm The best explanation: The intrinsic impedance of the TRANSVERSE magnetic wave is given by ηTM = η √(1-(fc/f)^2). Here the term √(1-(fc/f)^2) is always lesser than unity. Thus the intrinsic impedance of the TM wave is lesser than 377 ohms.

Discussion

50.	The v number of a waveguide having 120 modes is(a) 15.5(b) 18(c) 24(d) 12I had been asked this question in my homework.Question is from Transverse Magnetic Waves(TM) topic in chapter Waveguides of Electromagnetic Theory
Answer» Correct choice is (a) 15.5 Easy EXPLANATION: The NUMBER of modes in a waveguide is given by m = V^2/2. On substituting for m = 120, we GET V = √(2 X 120) = 15.5.

Discussion

Explore topic-wise InterviewSolutions in .

The number of modes in a waveguide having a V number of 10 is(a) 10(b) 25(c) 100(d) 50I got this question in class test.Query is from Transverse Electric Waves(TE) topic in division Waveguides of Electromagnetic Theory

The dominant mode in rectangular waveguide is(a) TE01(b) TE10(c) TM01(d) TM10I got this question during an interview.Origin of the question is Transverse Electric Waves(TE) in chapter Waveguides of Electromagnetic Theory

The exciter of the waveguide in a transmission line is the(a) Transmitter(b) Receiver(c) Transponder(d) AntennaThis question was addressed to me at a job interview.My question is taken from Transients topic in portion Waveguides of Electromagnetic Theory

The phase of the wave after the installation of the guided terminations will be(a) 0(b) 45(c) 90(d) 180The question was asked by my school teacher while I was bunking the class.My question is taken from Transients in chapter Waveguides of Electromagnetic Theory

The power of a wave having an electric field strength of 12.8 units is(a) 0.217(b) 0.721(c) 0.127(d) 0.172I have been asked this question during a job interview.This intriguing question originated from Transients in chapter Waveguides of Electromagnetic Theory

The power of a wave having a magnetic field intensity of 2.5 units is(a) 1.17 kilo watt(b) 1.17 mega watt(c) 1.17 watt(d) 11.7 wattI had been asked this question during an interview.My question comes from Transients in division Waveguides of Electromagnetic Theory

The power of a wave in a transmission line, when the current and the resistance are 5A and 120 ohm respectively is(a) 3000(b) 4000(c) 2000(d) 1500The question was asked in quiz.Enquiry is from Transients topic in section Waveguides of Electromagnetic Theory

When a waveguide is terminated, the mode of the guided termination will be(a) zero(b) non-zero(c) infinite(d) does not existI have been asked this question in an international level competition.I need to ask this question from Transients topic in section Waveguides of Electromagnetic Theory

The resonant circuit in a waveguide refers to the(a) Tank circuit(b) RC circuit(c) Bridge circuit(d) Attenuator circuitThe question was asked in final exam.This is a very interesting question from Transients in division Waveguides of Electromagnetic Theory

Cavity wave meters are used to measure which parameter of the wave?(a) Wavelength(b) Reflection factor(c) Phase(d) FrequencyThis question was posed to me during an interview.This interesting question is from Waveguide Current and Excitation in division Waveguides of Electromagnetic Theory

One of the applications of the cavity resonators is duplexer in RADAR systems. State true/false.(a) True(b) FalseThis question was posed to me in an interview for job.The above asked question is from Waveguide Current and Excitation topic in portion Waveguides of Electromagnetic Theory

Which type of wave does the resonant cavity produce?(a) Standing waves(b) Guided waves(c) Transmitted waves(d) Attenuated wavesThis question was posed to me in an online quiz.My question is based upon Waveguide Current and Excitation in division Waveguides of Electromagnetic Theory

The source voltage of a 75ohm transmission line is given by 150V. Find the load current.(a) 0.5(b) 2(c) 4(d) 1This question was posed to me in exam.Enquiry is from Waveguide Current and Excitation topic in portion Waveguides of Electromagnetic Theory

The phase and group velocities does not depend on which of the following?(a) Frequency(b) Wavelength(c) Phase constant(d) Attenuation constantThis question was posed to me in a job interview.My doubt is from Phase and Group Velocity topic in section Waveguides of Electromagnetic Theory

The phase velocity refers to a group of waves and the group velocity refers to a single wave. State true/false.(a) True(b) FalseThe question was posed to me in my homework.The question is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory

The guided wavelength and the phase constant are related by(a) 2π/βg = λg(b) 1/βg = λg(c) 1/2πβg = λg(d) βg = λgThis question was addressed to me during an internship interview.My query is from Phase and Group Velocity topic in division Waveguides of Electromagnetic Theory

The group velocity of a wave with a phase velocity of 60 x 10^9 is (in 10^6 order)(a) 1.5(b) 2(c) 2.5(d) 3I had been asked this question in a national level competition.This question is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory

The cut off wavelength of the rectangular waveguide in dominant mode with dimensions 6 cm x 4 cm is(a) 12cm(b) 6cm(c) 4cm(d) 2cmThe question was posed to me in semester exam.I'm obligated to ask this question of Phase and Group Velocity topic in portion Waveguides of Electromagnetic Theory

The product of the phase and the group velocities is given by the(a) Speed of light(b) Speed of light/2(c) 2 x Speed of light(d) (speed of light)/4The question was posed to me during an internship interview.Query is from Phase and Group Velocity in portion Waveguides of Electromagnetic Theory

The cut off wavelength and the guided wavelength are given by 0.5 and 2 units respectively. Find the wavelength of the wave.(a) 0.48(b) 0.32(c) 0.45(d) 0.54I got this question in an interview.This key question is from Phase and Group Velocity in chapter Waveguides of Electromagnetic Theory

The term cos θ is given by 2.5. Find the phase velocity.(a) 3(b) 5(c) 7.5(d) 2.5I have been asked this question in quiz.I would like to ask this question from Phase and Group Velocity in division Waveguides of Electromagnetic Theory

For a TEM wave to propagate in a medium, the medium has to be(a) Air(b) Insulator(c) Dispersive(d) Non dispersiveThis question was posed to me in semester exam.Question is taken from Transverse Electric Magnetic Waves(TEM) in portion Waveguides of Electromagnetic Theory

The guided phase constant of a TEM wave in a waveguide with a phase constant of 2.8 units is(a) 2.8(b) 1.4(c) 0(d) InfinityThe question was posed to me in an interview for internship.My question comes from Transverse Electric Magnetic Waves(TEM) in chapter Waveguides of Electromagnetic Theory

The guided wavelength of a TEM wave in a waveguide having a wavelength of 5 units is(a) 0(b) Infinity(c) 5(d) 1/5I have been asked this question in examination.Question is taken from Transverse Electric Magnetic Waves(TEM) in portion Waveguides of Electromagnetic Theory

The cut off wavelength in the TEM wave will be(a) 0(b) Negative(c) Infinity(d) 1/6 GHzI got this question in final exam.This key question is from Transverse Electric Magnetic Waves(TEM) topic in section Waveguides of Electromagnetic Theory

TEM wave can propagate in rectangular waveguides. State true/false.(a) True(b) FalseThis question was posed to me in exam.This intriguing question comes from Transverse Electric Magnetic Waves(TEM) topic in portion Waveguides of Electromagnetic Theory

Which component is non zero in a TEM wave?(a) Ex(b) Hz(c) Ez(d) Attenuation constantThis question was posed to me by my school principal while I was bunking the class.I'm obligated to ask this question of Transverse Electric Magnetic Waves(TEM) topic in chapter Waveguides of Electromagnetic Theory

The cut off frequency of the TEM wave is(a) 0(b) 1 GHz(c) 6 GHz(d) infinityI had been asked this question in a job interview.I want to ask this question from Transverse Electric Magnetic Waves(TEM) in chapter Waveguides of Electromagnetic Theory

The reflection coefficient, when a resonant cavity is placed between the waveguide is(a) 0(b) 1(c) -1(d) InfiniteI had been asked this question in an international level competition.Origin of the question is Transverse Magnetic Waves(TM) in division Waveguides of Electromagnetic Theory

Does the mode TM30 exists?(a) Yes(b) NoI got this question in an international level competition.Asked question is from Transverse Magnetic Waves(TM) in portion Waveguides of Electromagnetic Theory

Two modes with same cut off frequency are said to be(a) Generate modes(b) Dominant modes(c) Degenerate modes(d) Regenerate modesI got this question in a national level competition.I want to ask this question from Transverse Magnetic Waves(TM) topic in chapter Waveguides of Electromagnetic Theory

The intrinsic impedance of a TM wave will be(a) Greater than 377 ohm(b) Equal to 377 ohm(c) Lesser than 377 ohm(d) Does not existThe question was posed to me in semester exam.My question is taken from Transverse Magnetic Waves(TM) in portion Waveguides of Electromagnetic Theory

The v number of a waveguide having 120 modes is(a) 15.5(b) 18(c) 24(d) 12I had been asked this question in my homework.Question is from Transverse Magnetic Waves(TM) topic in chapter Waveguides of Electromagnetic Theory