Transmission Lines and Waveguides MCQs

Question 1

Regarding stubs which statement is not correct?

Accepted Answer

generally, they are longer than X/2

Answer

stubs are used for eliminating standing waves on a transmission line

Answer

they are usually placed in parallel with the transmission line close to the load end of the line

Answer

they are nothing else but short sections of the transmission line either open-circuited or short circuited

Question 2

Indicate the FALSE statement. Higher the value of SWR of a transmission line,

Accepted Answer

higher the velocity factor

Answer

greater the mismatch between line and load

Answer

greater the power loss

Answer

more the noise

Question 3

Which one of the following statements is WRONG? If the SWR of a transmission line is infinity, it is terminated in a/an

Accepted Answer

complex impedance

Answer

short circuit

Answer

open circuit

Answer

pure reactance

Question 4

The velocity factor of a transmission line

Accepted Answer

depends on the permittivity of the surrounding medium

Answer

is always greater than unity

Answer

is least for air medium

Answer

is governed by skin effect

Question 5

Impedance inversion at radio frequencies may be applied with the help of a/an

Accepted Answer

quarter-wave transformer

Answer

half-wave line

Answer

short-circuited stub

Answer

open-circuited stub

Question 6

Indicate the FALSE statement.

Accepted Answer

a short-circuit line less than X/4 long behaves like a pure capacitance

Answer

a piece of line X/4 long and shortcircuited at the far end looks like an open circuit and behaves like a parallel-tuned circuit

Answer

an open-circuited line less than X/4 long behaves like a purecapacitance

Answer

a line k12 long an open-circuited at far end behaves like a parallel-tuned circuit

Question 7

Short-circuited stubs are preferred to open-circuited ones because they

Accepted Answer

are not liable to radiate

Answer

are easier to make

Answer

have variable matching properties

Answer

are made of the same transmission line as the one to which they are connected

Question 8

For connecting an unbalanced ecoaxial line to a balanced antenna, we may use

Accepted Answer

a balun

Answer

double stub

Answer

directional coupler

Answer

a slotted line

Question 9

A waveguide behaves as a ___filter.

Accepted Answer

high-pass

Answer

low-pass

Answer

band-pass

Answer

band-elimination