1
GATE ECE 2000
+2
-0.6
A rectangular waveguide has dimensions $$1\,\,cm\,\, \times \,\,0.5\,\,cm$$. Its cut-off frequency is
A
5 GHz
B
10 GHz
C
15 GHz
D
20 GHz
2
GATE ECE 1993
+2
-0.6
An optical fiber consists of a cylindrical dielectric rod of refractive index $$n_1$$, surrounded by another dielectric of refractive index $$n_2$$ where $$n_2$$ < $$n_1$$ as shown in the following Fig. If a ray is incident from air at angle i to the axis, then it undergoes total internal reflection at the interface AB if A
$$i\,\, \ge \,\,{\sin ^{ - 1}}\,\sqrt {{n_1}^2 - {n_2}^2}$$
B
$$i\,\, < \,\,{\sin ^{ - 1}}\,\sqrt {{n_1} - {n_2}}$$
C
$$i\,\, \le \,\,{\sin ^{ - 1}}\,\sqrt {{n_1}^2 - {n_2}^2}$$
D
$$i\,\, = \,\,{\sin ^{ - 1}}\,\sqrt {{n_1} - {n_2}}$$
3
GATE ECE 1990
MCQ (More than One Correct Answer)
+2
-0.6
Choose the correct statements.
For a wave propagating in an air filled rectangular wave guide
A
Guided wavelength is never less than the free space wavelength
B
Wave impedance is never less than the free space impedance.
C
Phase velocity is never less than the free space velocity
D
TEM mode is possible if the dimensions of the wave guide are properly chosen.
4
GATE ECE 1988
MCQ (More than One Correct Answer)
+2
-0.6
For a normal mode EM wave propagating in a hollow rectangular wave guide
A
the phase velocity is greater than the group velocity
B
the phase velocity is greater than velocity of light in free space
C
the phase velocity is less than the velocity of light in free space
D
the phase velocity may be either greater than or less than the group velocity
GATE ECE Subjects
Network Theory
Control Systems
Electronic Devices and VLSI
Analog Circuits
Digital Circuits
Microprocessors
Signals and Systems
Communications
Electromagnetics
General Aptitude
Engineering Mathematics
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