1
GATE ECE 2011
MCQ (Single Correct Answer)
+1
-0.3
A transmission line of characteristic impedance 50 $$\Omega $$ is terminated by a 50 $$\Omega $$ load. When excited by a sinusoidal voltage source at 10 GHz, the phase difference between two points spaced 2 mm apart on the line is found to be $$\pi /4$$ radians. The phase velocity of the wave along the line is
A
$$0.8\,\, \times \,\,{10^8}\,m/s$$
B
$$1.2\,\, \times \,\,{10^8}\,m/s$$
C
$$1.6\,\, \times \,\,{10^8}\,m/s$$
D
$$3\,\, \times \,\,{10^8}\,m/s$$
2
GATE ECE 2011
MCQ (Single Correct Answer)
+2
-0.6
A transmission line of characteristic impedance 50 $$\Omega $$ is terminated in a load impedance $$Z_L$$. The VSWR of the line is measured as 5 and the first of the voltage naxima in the line is observed at a distance of $$\lambda /4$$ from the load. The value of $$Z_L$$ is
A
10 $$\Omega $$
B
250 $$\Omega $$
C
(19.23 + j 46.15) $$\Omega $$
D
(19.23 - j 46.15)$$\Omega $$
3
GATE ECE 2011
MCQ (Single Correct Answer)
+2
-0.6
The electric and magnetic fields for a TEM wave of frequency $$14 GHz$$ in a homogeneous medium of relative permittivity $${\varepsilon _r}$$ and relative permeability $${\mu _r} = 1$$ are given by $$$\overrightarrow E = {E_p}\,\,{e^{j\left( {\omega t - 280\pi y} \right)}}\,\,{\widehat u_z}\,\,V/m$$$ $$$\overrightarrow H = \,\,3\,\,{e^{j\left( {\omega \,t - 280\,\,\pi \,y} \right)}}\,\,\widehat u{\,_x}\,\,A/m$$$

Assuming the speed of light in free space to be $$3\,\, \times {10^8}\,\,\,m/s,$$ the intrinsic impedance of free space to be $$120\,\,\,\pi $$, the relative permittivity $${\varepsilon _r}$$ of the medium and the electric field amplitude $${E_p}$$ are

A
$${\varepsilon _r} = 3,\,\,{E_p} = 120\,\pi $$
B
$${\varepsilon _r} = 3,\,\,{E_p} = 360\,\pi $$
C
$${\varepsilon _r} = 9,\,\,{E_p} = 360\,\pi $$
D
$${\varepsilon _r} = 9,\,\,{E_p} = 120\,\pi $$
4
GATE ECE 2011
MCQ (Single Correct Answer)
+1
-0.3
The modes in a rectangular waveguide are denoted by $$T{E_{mn}}\,$$/$$T{M_{mn}}\,$$ where m and n are the eigen numbers along the larger and smaller dimensions of the waveguide respectively. Which one of the following satements is TRUE?
A
The $$T{M_{10}}\,$$ mode of the waveguide does not exist
B
The $$T{E_{10}}\,$$ mode of the waveguide does not exist
C
The $$T{M_{10}}\,$$ and the $$T{E_{10}}\,$$ modes both exist and have the same cut-off frequencies
D
The $$T{M_{10}}\,$$ and the $$T{M_{01}}\,$$ modes both exist and have the same cut-off frequencies.
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