Transmission Lines and Waveguides MCQs

Question 1

On a resistively terminated high frequency loss-loss transmission line fed by a 500 MHz source, the VSWR is found to be equal to 2 and the first voltage minimum is measured at 30 cm from the load end. What is the value of the "normalised" load resistance?

Accepted Answer

1

Answer

3

Answer

2

Answer

4

Question 2

For a quarter wavelength ideal transmission line of characteristic impedance 50 ohms and load impedance 100 ohms, the input impedance will be

Accepted Answer

25

Answer

50 SI

Answer

100 SI

Answer

150 Q

Question 3

The reflection co-efficient on a line is 0.2 - 45?. the SWR of this line is

Accepted Answer

1.5

Answer

0.8

Answer

1.1

Answer

1.2

Question 4

For a transmission line the, propagation constant, for a TEM wave travelling in it, is given by (where the symbols have the usual meanings)

Accepted Answer

[(R + jcoL) (G +koC)] ?

Answer

[(R+ jtaL)(G +koC)]

Answer

[(R - jo.)L)(G + jcoC)] ?

Answer

[(R - jcoL)(G + jc.o2C)] 1/3

Question 5

A lossless, air dielectric cylindrical wave guide of inside diameter 3cm, is operated at 14GHz. For the TMii mode propagating in +z direction, the wave impedance will be (for TM iv mode, K a =3.832)

Accepted Answer

185 Q

Answer

120 TEO

Answer

240 7cf2

Answer

95.25

Question 6

Choose the correct statements for a wave proparating in an air filled rectangular wave guide :

Accepted Answer

Guided wavelength is never less than the free space wavelength

Answer

Wave impedance is never less than the free space impedance

Answer

Phase velocities is never less than the free space velocity

Answer

TEM mode is possible if the dimensions of the wave guide are properly chosen

Question 7

Assuming perfect conductor of a transmission line, pure TEM propagation is NOT possible in

Accepted Answer

semi infinite parallel plate wave guide

Answer

coaxial cable

Answer

air filled cylindical wave guide

Answer

parallel thin wire line in air

Question 8

The dominant mode in a rectangular wave guide is TE0, because this mode has

Accepted Answer

the highest cut off wavelengt:;

Answer

no attenuation

Answer

no cut off

Answer

no megnetic field component

Question 9

When electromagetic waves are propagated in a waveguide

Accepted Answer

they are reflected from the walls but do not travel along them

Answer

they travel along the broader walls of the guide

Answer

they travel through the dielectric without tuuching the walls

Answer

they travel along all four walls of the waveguide