GATE ECE 1990 | GATE ECE Year Wise Previous Years Questions

GATE ECE 1990

Subjective

-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 $$\varepsilon = {1 \over {36\pi }} \times {10^{ - 9}}$$ $$F/m$$

GATE ECE 1990

MCQ (Single Correct Answer)

-0.6

Two isotropic antennas are separated by a distance of two wavelengths. If both the antennas are fed with currents of equal phase and magnitude, the number of lobes in the radiation pattern in the horizontal plane are

GATE ECE 1990

MCQ (Single Correct Answer)

-0.3

In a junction diode

The depletion capacitance increases with increase in the reverse bias

The depletion capacitance decreases with increase in the reverse bias

The depletion capacitance increases with increase in the forward bias

The depletion capacitance is much higher than the depletion capacitance when it is forward bias.

GATE ECE 1990

MCQ (Single Correct Answer)

-0.6

If the Laplace transform of the voltage across a capacitor of value of $$\frac12\;\mathrm F$$ is $$V_C\;\left(s\right)\;=\;\frac{s\;+\;1}{s^3\;+\;s^2\;+\;s\;+\;1}$$ , the value of the current through the capacitor at t = 0⁺ is

0 A

2 A

$$\frac12\;\mathrm A$$

1 A

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