1
GATE ECE 2012
MCQ (Single Correct Answer)
+1
-0.3
A plane wave propagating in air with $$\vec E = \left( {8{{\widehat a}_x} + 6{{\widehat a}_y} + 5{{\widehat a}_z}} \right){\mkern 1mu} {\mkern 1mu} {e^{j\left( {\omega t + 3x - 4y} \right)}}{\mkern 1mu} {\mkern 1mu} V/m$$ is incident on a perfectly conducting slab positioned at $$x \le 0$$. The $$\overrightarrow E $$ field of the reflected wave is
A
$$\left( { - 8{{\widehat a}_x} - 6{{\widehat a}_y} - 5{{\widehat a}_z}} \right){\mkern 1mu} {e^{j\left( {\omega t + 3x + 4y} \right)}}{\mkern 1mu} {\mkern 1mu} V/m$$
B
$$\left( { - 8{{\widehat a}_x} + 6{{\widehat a}_y} - 5{{\widehat a}_z}} \right){\mkern 1mu} {e^{j\left( {\omega t + 3x + 4y} \right)}}{\mkern 1mu} {\mkern 1mu} V/m$$
C
$$\left( { - 8{{\widehat a}_x} - 6{{\widehat a}_y} - 5{{\widehat a}_z}} \right){\mkern 1mu} {e^{j\left( {\omega t - 3x - 4y} \right)}}{\mkern 1mu} {\mkern 1mu} V/m$$
D
$$\left( { - 8{{\widehat a}_x} + 6{{\widehat a}_y} - 5{{\widehat a}_z}} \right){\mkern 1mu} {e^{j\left( {\omega t - 3x - 4y} \right)}}{\mkern 1mu} {\mkern 1mu} V/m$$
2
GATE ECE 2012
MCQ (Single Correct Answer)
+1
-0.3
The radiation pattern of an antenna in spherical co-ordinates is given by $$$F\,(\theta )\, = {\cos ^4}\,\theta \,\,\,;\,\,0\,\, \le \,\,\theta \,\, \le \,\,\pi /2$$$ The directivity of the antenna is
A
10 dB
B
12.6 dB
C
11.5 dB
D
18 dB
3
GATE ECE 2012
MCQ (Single Correct Answer)
+2
-0.6
An infinitely long uniform solid wire of radius a carries a uniform dc current of density $$\widehat{\mathrm j}$$

The magnetic field at a distance r from the center of the wire is proportional to

A
r for r < a and 1/r2 for r > a
B
0 for r < a and 1/r for r > a
C
r for r < a and 1/r for r > a
D
0 for r < a and 1/r2 for r > a
4
GATE ECE 2012
MCQ (Single Correct Answer)
+2
-0.6
An infinitely long uniform solid wire of radius a carries a uniform dc current of density $$\widehat{\mathrm j}$$.

A hole of radius b (b < a) is now drilled along the length of the wire at a distance d from the center of the wire as shown below.

GATE ECE 2012 Electromagnetics - Maxwell Equations Question 28 English

The magnetic field inside the hole is

A
uniform and depends only on d
B
uniform and depends only on b
C
uniform and depends on both b and d
D
non uniform