Transmission Lines and Waveguides MCQs

A circuilar air filled waveguide of radius 5 cm is operated in the THoi mode. The waveguide is then completely filled with a dielectric of relative permittivity 2.25 and relative permeability 1.0. The cut-off wavelength for the THoi mode is 0.082 m when the waveguide is air-filled.When the waveguide is filled with the dielectric, the cut-off frequency will become nearly

In a rectangular waveguide there is one half-wave variation of a electric field across the narrow dimension and two half-wave variations of electric field across the wider dimension. What is the dominant mode?

Which one of the following statements is true for electro-magnetic wave propagation through a rectangular waveguide of cross section 2a x a?

The phase velocity of an electromagnetic wave propagating in a hollow metallic rectangular waveguide in the TE10 mode is

The longest wavelength that can be absorbed by silicon, which has the bandgap of 1.12 eV, is 1.1 pm. If the longest wavelength that can be absorbed by another material is 0.87 pm, then the bandgap of this material is

A lossless transmission line is terminated in a load which reflects a part of the incident power. The measured VSWR is 2. The percentage of the power that is reflected back is

Characteristic impedance of a transmission line is 500. Input impedance of the open-circuited line is Zoc = 100 + j150 Q. When the transmission line is short-circuited, then value of the input impedance will be

A 30-Volts battery with zero source resistance is connected to a coaxial line of characteristic impedance of 50 Ohms at t = 0 second and terminated in an unknown resistive load. The line length is such that it takes 400 gs for an electromagnetic wave to travel from source end to load end and vice-versa. At t = 400 gs, the voltage at the load end is found to be 40 Volts.I The load resistance is

A 30-Volts battery with zero source resistance is connected to a coaxial line of characteristic impedance of 50 Ohms at t = 0 second and terminated in an unknown resistive load. The line length is such that it takes 400 gs for an electromagnetic wave to travel from source end to load end and vice-versa. At t = 400 gs, the voltage at the load end is found to be 40 Volts The steady-state current through the load resistance is