1
GATE ECE 1992
Subjective
+8
-0
A uniform plane wave traveling in free space along the +$$z$$ direction and having its electric field along the$$x$$-direction, is normally incident on a thick brass sheet, infinite in extent (along the $$x$$-and $$y$$-directions). The electric field intensity of the wave is given by $${E_x} = 1225\,\cos \,\left( {5.89 \times {{10}^{10}}t - \beta z} \right)\,\,\,\,V/m$$\$.

Calculate the power per square metre that causes heating of the brass sheet, taking $${ \in _r} = 1,\,\,\,{\mu _r} = 1$$ and $$\sigma = 1.649 \times {10^7}\,\,\,\,\,$$ mhos/metre for brass.

2
GATE ECE 1991
Subjective
+8
-0
A uniform plane electromagnetic wave traveling in free-space enters into a lossless medium at normal incidence. In the medium its velocity reduces by 50% and in free space sets up a standing wave having a reflection coefficient of - 0.125. Calculate the permeability and the permittivity of the medium.
3
GATE ECE 1990
Subjective
+8
-0
A 300 MHz plane E.M. wave is propagating in free space. The wave is incident normally on an infinite copper slab. For the transmitted wave in the copper slab, calculate the following

(a) Attenuation constant
(b) Phase constant
(c) Skin depth
(d) Phase velocity and
(e) Group velocity

for copper assume the following values
Conductivity $$\sigma = 5.8 \times {10^7}$$ $$mho/m$$
Permeability $$\mu = 4\pi \times {10^{ - 7}}$$ $$H/m$$
Permeability $$\varepsilon = {1 \over {36\pi }} \times {10^{ - 9}}$$ $$F/m$$

4
GATE ECE 1987
Subjective
+8
-0
An electric field is given by $$\overrightarrow E = \overrightarrow a {}_x\,{\rm A}\,\,\sin \,\beta ySin\,\,\omega t$$ is present in a charge free medium infinite in extent

(a) Determine the associated magnetic field.
(b) What type of wave does the above field represent?

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