Description : The minimum impedance of a 75 ohm transmission line with a SWR of 2.5 is a) 100 b) 50 c) 25 d) 30
Last Answer : d) 30
Description : A load of 200 ohm is used to match 300 ohm transmission line to achieve SWR=1. Find out the required characteristic impedance of a quarter of a quarter wave transformer connected directly to the load.
Last Answer : Solution :
Description : Find the standing wave ratio, when a load impedance of 250 ohm is connected to a 75 ohm line. a) 0.3 b) 75 c) 250 d) 3.33
Last Answer : d) 3.33
Description : A transmission line of unknown impedance is terminated with two different resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the line? A. 100 Ω B. 212 Ω C. 300 Ω D. 112 Ω
Last Answer : D. 112 Ω
Description : The intrinsic impedance of free space is given by a) 272 ohm b) 412 ohm c) 740 ohm d) 377 ohm
Last Answer : d) 377 ohm
Description : The input impedance of a short circuited loss less transmission line of characteristic impedance 50 Ohm is
Last Answer : Capacitive
Description : Find the reflection coefficient of the wave with SWR of 3.5. a) 0.55 b) 0.23 c) 0.48 d) 0.68
Last Answer : a) 0.55
Description : Given that the reflection coefficient is 0.6. Find the SWR. a) 2 b) 4 c) 6 d) 8
Last Answer : b) 4
Description : The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is: (1) 25 ohm (2) 50 ohm (3) 75 ohm (4) 100 ohm
Last Answer : The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is 25 ohm.
Description : A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is?
Last Answer : A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is 0.6 lagging.
Description : Standing waves occurs due to a) Impedance match b) Impedance mismatch c) Reflection d) Transmission
Last Answer : b) Impedance mismatch
Description : What is the input impedance of a transmission line if its characteristic impedance is 300 Ω and the load is 600 Ω? Assume a quarter wavelength section only. A. 150 kΩ B. 150 mΩ C. 150 Ω D. 2 Ω
Last Answer : C. 150 Ω
Description : The outer conductor of a coaxial transmission line is always grounded at the A. Input only B. Input and output C. Output only D. Point of high SWR
Last Answer : B. Input and output
Description : a) For a transmission line, Find SWR and reflection coefficient R if, i. There is no reflected voltage. ii. Reflected voltage and incident voltage is equal. iii. If reflected voltage=20V and incident voltage=10V. iv. If reflected voltage=10V and incident voltage =20V.
Last Answer : reflection coefficient R=Vr/Vi i. There is no reflected voltage. i.e,Vr=0 R=0 SWR= 1+R/1-R=1 ii. Reflected voltage and incident voltage is equal. Vr=Vi; R=1 SWR= 1+R/1-R=1+1/1-1=infinity iii. If reflected ... and incident voltage =20V. Vr=10 and Vi=20 R=10/20=0.5 SWR= 1+R/1-R=1+.5/1-.5=3
Description : For a transmission line, the incident voltage. Ei = 6V and Er =2V ,Calculate: (i) Reflection Coefficient (ii) SWR
Last Answer : Reflection Coefficient(K) = Er / Ei = 2V / 6V K = 0.333 SWR = 1+K / 1- K = 1+0.333 / 1-0.333 = 1.333 / 0.667 SWR= 1.998
Description : What is the input terminal impedance at the center if a folded dipole antenna? A. 300 ohms B. 72 ohms C. 50 ohms D. 450 ohms
Last Answer : A. 300 ohms
Description : Find the ratio of the refractive index of medium 1 to that of medium 2, when the incident and reflected angles are given by 300 and 450 respectively. a) 0.5 b) 1 c) 2 d) 4
Last Answer : c) 2
Description : What is the electric field intensity at a distance of 20cm from a charge 2 X 10 -6 C in vacuum? a) 250,000 b) 350,000 c) 450,000 d) 550,000
Last Answer : c) 450,000
Description : Convert the point (3,4,5) from Cartesian to spherical coordinates a) (7.07,450,530) b) (0.707,450,530) c) (7.07,540,630) d) (0.707,540,630)
Last Answer : a) (7.07,450,530)
Description : The effective skin resistance of a material with conductivity 120 and skin depth of 2μm is a) 4.16 kilo ohm b) 4.16 mega ohm c) 41.6 kilo ohm d) 41.6 mega ohm
Last Answer : a) 4.16 kilo ohm
Description : Find the dissipation factor when series resistance is 5 ohm and capacitive resistance is 10 unit. a) 2 b) 0.5 c) 1 d) 0
Last Answer : b) 0.5
Description : Find the time constant in a series R-L circuit when the resistance is 4 ohm and the inductance is 2 H. a) 0.25 b) 0.2 c) 2 d) 0.5
Last Answer : d) 0.5
Description : Find the current in a conductor with resistance 2 ohm, electric field 2 units and distance 100cm. a) 1A b) 10mA c) 10A d) 100mA
Last Answer : a) 1A
Description : The resistivity of a material with resistance 200 ohm, length 10m and area twice that of the length is a) 200 b) 300 c) 400 d) 500
Last Answer : c) 400
Description : The lossless line of characteristics impedance 300 Ohm is terminated in a pure resistance of 200 Ohm. The value of the standing wave ratio is (a) 1.5 (b) 0.67 (c) 1.0 (d) 1.25
Last Answer : The lossless line of characteristics impedance 300 Ohm is terminated in a pure resistance of 200 Ohm. The value of the standing wave ratio is 1.5
Description : The work done in the power transmission with E and H given by 50 and 65 respectively. The velocity of propagation is 20m/s. a) 162.5 b) 621.5 c) 562.1 d) 261.5
Last Answer : a) 162.5
Description : The expression for intrinsic impedance is given by a) √(με) b) (με) c) √(μ/ε) d) (μ/ε)
Last Answer : c) √(μ/ε)
Description : The phase shift in the electric and magnetic fields in an EM wave is given by which parameter? a) phase constant b) attenuation constant c) propagation constant d) intrinsic impedance
Last Answer : d) intrinsic impedance
Description : The intrinsic impedance of free space is a) 489 b) 265 c) 192 d) 377
Last Answer : d) 377
Description : The intrinsic impedance is the ratio of square root of a) Permittivity to permeability b) Permeability to permittivity c) Phase constant to wavelength d) Wavelength to phase constant
Last Answer : b) Permeability to permittivity
Description : A radio frequency in the ultra high frequency band of the radio spectrum band. A. 235.50 MHz B. 450.50 MHz C. 150.50 GHz D. 0.31250 GHz
Last Answer : D. 0.31250 GHz
Description : Operating temperature and pressure in catalytic reforming is about (A) 1-5 Kgf/cm2 & 200°C (B) 15-45 Kgf/cm2 & 450-550°C (C) 50 - 75 kgf/cm2 & 600 - 800°C (D) 5-10 kgf/cm2 & 150 - 250°C
Last Answer : (B) 15-45 Kgf/cm2 & 450-550°C
Description : Which of the following is not common transmission line impedance? A. 50 ohms B. 120 ohms C. 75 ohms D. 650 ohms
Last Answer : B. 120 ohms
Description : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.
Last Answer : The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.
Description : The benefit of Maxwell equation is that a) Any parameter can be calculated b) Antenna can be designed c) Polarisation of the wave can be calculated d) Transmission line constants can be found
Last Answer : a) Any parameter can be calculated
Description : Alternating current measured in a transmission line will be a) Peak value b) Average value c) RMS value d) Zero
Last Answer : c) RMS value
Description : Most of the plastics are safe to be used upto a maximum temperature of __________ °C. (A) 100 (B) 150 (C) 350 (D) 450
Last Answer : (B) 150
Description : Most mobile satellite array uses ___________ in transforming 50 to 150 Ω impedance. A. stub B. balun C. quarter-wavelength transformer D. microstrip tapers.
Last Answer : C. quarter-wavelength transformer
Description : Find the conduction current density of a material with conductivity 200units and electric field 1.5 units. a) 150 b) 30 c) 400/3 d) 300
Last Answer : d) 300
Description : Find the electric field when the velocity of the field is 12m/s and the flux density is 8.75 units. a) 510 b) 105 c) 150 d) 165
Last Answer : b) 105
Description : When troubleshooting most electronic circuits, 'loading effect' can be minimized by using a voltmeter with a/an ___________________. A. input impedance much greater than the impedance across which the voltage ... sensitivity of less than 1000 ohms/volt D. sensitivity of more than 1000 volts/ohm
Last Answer : Answer: A
Description : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be
Last Answer : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be 0.5 Ohm
Description : If the operating frequency is 450 MHz what length of a pair of conductors is considered to be a transmission line? A. 2.19 ft B. 2.19 m C. 0.219 ft D. 0.219 m
Last Answer : C. 0.219 ft
Description : The voltage at the two ends of a transmission line are 132 KV and its reactance is 40 ohm. The Capacity of the line is (A) 435.6 MW (B) 217.8 MW (C) 251.5 MW (D) 500 MW
Last Answer : (A) 435.6 MW
Description : Calculate the transmission coefficient of a wave with a reflection coefficient of 0.6 a) 0.6 b) 1 c) 0 d) 0.4
Last Answer : d) 0.4
Description : The transmission coefficient of a wave with incident and transmitted electric field of 5 and 5 respectively is a) 0 b) 1 c) 10 d) 5
Last Answer : b) 1
Description : The angle of incidence of a wave of a wave with angle of transmission 45 degree and the refractive indices of the two media given by 2 and 1.3 is a) 41.68 b) 61.86 c) 12.23 d) 27.89
Last Answer : a) 41.68
Description : The Brewster angle is the angle of a) Incidence b) Reflection c) Refraction d) Transmission
Last Answer : a) Incidence
Description : The transmission coefficient of a wave propagating in the Brewster angle is a) 0 b) 1 c) -1 d) Infinity
Description : The velocity of a wave travelling in the air medium without transmission lines or waveguides(wireless) is a) 6 x 10 8 b) 3 x 10 8 c) 1.5 x 10 8 d) 9 x 10 8
Last Answer : b) 3 x 10 8