1
GATE ECE 2007
MCQ (Single Correct Answer)
+1
-0.3
A plane wave of wavelength $$\lambda $$ is traveling in a direction making an angle $${{{30}^ \circ }}$$ with positive $$x$$-axis and $${{{90}^ \circ }}$$ with positiv $$y$$-axis. The $$\overrightarrow E $$ field of the plane wave can be represented as ($${E_0}$$ is a constant)
A
$$\vec E = \widehat y\,\,{E_0}{\mkern 1mu} {e^{j\left( {\omega t - {{\sqrt 3 {\kern 1pt} \pi } \over \lambda }x - {\pi \over \lambda }z} \right)}}$$
B
$$\vec E = \widehat y\,\,{E_0}{\mkern 1mu} {e^{j\left( {\omega t - {\pi \over \lambda }x - {{\sqrt 3 {\kern 1pt} \pi } \over \lambda }z} \right)}}$$
C
$$\vec E = \widehat y\,\,{E_0}{\mkern 1mu} {e^{j\left( {\omega t + {{\sqrt 3 {\kern 1pt} \pi } \over \lambda }x + {\pi \over \lambda }z} \right)}}$$
D
$$\vec E = \widehat y\,\,{\mkern 1mu} {E_0}{\mkern 1mu} {e^{j\left( {\omega t - {\pi \over \lambda }x + {{\sqrt 3 {\kern 1pt} \pi } \over \lambda }z} \right)}}$$
2
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
An air-filled rectangular waveguide has inner dimensions of $$3\,cm\,\, \times \,\,2\,\,cm\,$$. The wave impedance of the $$T{E_{20}}$$ mode of propagation in the waveguide at a frequency of 30 GHz is (free space impedance $$\,{\eta _0} = \,377\,\,\Omega $$)
A
308 $$\Omega $$
B
355 $$\Omega $$
C
400 $$\Omega $$
D
461 $$\Omega $$
3
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
The $$\mathop E\limits^ \to $$ field in a rectangular waveguide of inner dimensions $$a\,\, \times \,\,b$$ is given by $$\mathop E\limits^ \to = {{\omega \,\mu } \over {{h^2}}}\,\left( {{\pi \over a}} \right)\,{H_0}\,\sin \,\left( {{{2\,\pi \,x} \over a}} \right)\,\,\sin \,(\omega \,t - \,\beta \,z)\hat y$$,

where $${H_0}$$ is a constant, a and b are the dimensions along the x-axis and the y-axis respectively. The mode of propagation in the waveguide is

A
$$T{E_{20}}$$
B
$$T{M_{11}}$$
C
$$T{M_{20}}$$
D
$$T{E_{10}}$$
4
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
The $$\overrightarrow H $$ field (in A/m) of a plane wave propagating in free space is given by $$$\overrightarrow H = \widehat x{{5\sqrt 3 } \over {{\eta _0}}}\cos \left( {\omega \,t - \beta \,z} \right) + \widehat y{5 \over {{\eta _0}}}\sin \left( {\omega \,t - \beta \,z + {\pi \over 2}} \right)$$$

The time average power flow density in Watts is

A
$${{{\eta _0}} \over {100}}$$
B
$${{100} \over {{\eta _0}}}$$
C
$$50\,{\eta _0}^2$$
D
$${{50} \over {{\eta _0}}}$$