GATE EC Electromagnetics questions

Practise Electromagnetics questions for GATE EC. Explore official PYQs and original subject-wise quizzes, check answers and view available solutions. Free, no sign-in.

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SubjectTopicYearType

Two coaxial cables

1

2

are filled with different dielectric constants

\varepsilon_{r 1}

\varepsilon_{r 2}

respectively. The ratio of the wavelengths in the two cables,

\left(\lambda_{1} / \lambda_{2}\right)

A rectangular waveguide has dimensions

1 \mathrm{~cm} \times 0.5 \mathrm{~cm}

. Its cut-off frequency is

A rectangular waveguide has dimensions

1 \mathrm{~cm} \times 0.5 \mathrm{~cm}

. Its cut-off frequency is

8

(2.4 \mathrm{~m})

parabolic dish antenna operating at

4 \; \mathrm{GHz}

, the minimum distance required for far field measurement is closest to

A uniform plane wave in air impinges at

45^{\circ}

angle on a lossless dielectric material with dielectric constant

\varepsilon_{r}

. The transmitted wave propagates in a

30^{\circ}

direction with respect to the normal. The value of

\varepsilon_{r}

Identify which one of the following will

\text{NOT}

satisfy the wave equation.

Indicate which one of the following will

\text{NOT}

exist in a rectangular resonant cavity.

Assuming perfect conductors of a transmission line, pure

\text{TEM}

\text{NOT}

An electric field on a plane is described by its potential

\mathrm{V}=20\left(r^{-1}+r^{-2}\right)

r

is the distance from the source. The field is due to

A plane wave propagating through a medium

\left[\varepsilon_{\mathrm{r}}=8, v_{\mathrm{r}}=2\right.

\left.\sigma=0\right]

has its electric field given by

\overrightarrow{\mathrm{E}}=0.5 \hat{\mathrm{X}} \mathrm{e}^{-(z / 3)} \sin \left(10^{8} t-\beta z\right) \mathrm{V} / \mathrm{m}

. The wave impedance, in ohms is

In air, a lossless transmission line of length

50 \mathrm{~cm}

\mathrm{L}=10 \; \mu \mathrm{H} / \mathrm{m}, \mathrm{C}=40 \; \mathrm{pF} / \mathrm{m}

25 \; \mathrm{MHz}

. Its electrical path length is

A trasmitting antenna radiates

251 \mathrm{~W}

isotropically. A receiving antenna, located

100 \mathrm{~m}

away from the transmitting antenna, has an effective aperture of

500 \mathrm{~cm}^{2}

. The total received by the antenna is

In a twin-wire transmission line in air, the adjacent voltage maxima are at

12.5 \mathrm{~cm}

27.5 \mathrm{~cm}

. The operating frequency is

A high-Q quartz crystal exhibits series resonance at the frequency

\omega_{s}

and parallel resonance at the frequency

\omega_{p}

The far field of an antenna varies with distance

\mathrm{r}

A loop is rotating about the

y

-axis in a magnetic field

\overrightarrow{\mathrm{E}}=\mathrm{B}_{0} \cos (\omega t+\phi) \vec{a}_{x} \mathrm{~T}

. The voltage in the loop is

An antenna in free space receives

2 \; \mu \mathrm{W}

of power when the incident electric field is

20 \mathrm{~m} \; \mathrm{V} / \mathrm{m} \; \mathrm{rms}

. The effective aperture of the antenna is

The radiation resistance of a circular loop of one turn is

0.01 \; \Omega

. The radiation resistance of five turns of such a loop will be

\mathrm{H}

in the far field of an antenna satisfies

The polarisation of wave with electric field vector

\overrightarrow{\mathrm{E}}=\mathrm{E}_{0} \; e^{j(\hat{\rho}(\omega t+\beta z)}\left(\vec{a}_{x}+\vec{a}_{y}\right)