Recent activity in Electromagnetics

A complex load (in $\Omega$ ) is represented as $\Gamma_{L}=0.5 \angle 30^{\circ}$ on the Smith chart. A co-axial cable with a characteristic impedance of $50 ~\Omega$ is...

The cutoff frequency ( $\text{in GHz}$ ) for the dominant $\mathrm{TE}_{10}$ mode of an air-filled rectangular waveguide of inner dimension $0.28$ inch $\times 0.14$ inch...

The electric field of a monochromatic plane wave travelling in a lossless isotropic and homogenous medium is given by\[\vec{E}(z, t)=E_{0}[\hat{x} \cos (\omega t-k z)+\ha...

Consider the Friis' transmission equation $P_{R}=\left(P_{T} G_{T} G_{R} \lambda^{2}\right) /(4 \pi D)^{2}$, where $P_{R}$ and $P_{T}$ are the received and the transmitte...

The intrinsic impedance of a lossy dielectric medium is given by$\frac{j \omega \mu}{\sigma}$$\frac{j \omega \varepsilon}{\mu}$$\sqrt{\frac{j \omega \mu}{\sigma+j \omega ...

A material is described by the following electrical parameters as a frequency of $10 \; \mathrm{GHz}, \sigma=10^{6} \mathrm{mho} / \mathrm{m}, \mu=\mu^{0}$ and $\sigma / ...

While you are listening to a programme from a radio, if a near-by electric light bulb is switched on or switched off, you hear a momentary noise in your radio. This is du...

Consider the periodic square wave in the figure shown. The ratio of the power in the $7^{th}$ harm...

Concentric spherical shells of radii $2$m, $4$m, and $8$ m carry uniform surface charge densities of $20 \: nC/m^2$, $ – 4 \: nC/m^2$ and $\rho_s$ respectively. The value...

Nuclear fusion reactions require very high temperatures so as to overcome.nuclear forcesvan der waals forcescoulomb forcesgravitational forces

Two particles of masses $M_{1}$ and $M_{2}\left(M_{1}>M_{2}\right)$ attract each other with a force inversely proportional to the square of the distance between them. The...

The force on a point charge $+q$ kept at a distance $d$ from the surface of an infinite grounded metal plate in a medium of permittivity $\epsilon\:$ is$0$$\dfrac{q^{2}}...

An antenna with a directive gain of $6\text{ dB}$ is radiating a total power of $\text{16 kW}$. The amplitude of the electric field in free space at a distance of $\text{...

A standard air-filled rectangular waveguide with dimensions $\text{a=8 cm, b=4 cm}$, operates at $\text{3.4 GHz}$. For the dominant mode of wave propagation, the phase ve...

The refractive indices of the core and cladding of an optical fiber are $1.50$ and $1.48$, respectively. The critical propagation angle, which is defined as the maximum a...

In the radiation pattern of a $3$-element array of isotropic radiators equally spaced at distances of $\frac{\lambda}{4}$ it is required to place a null at an angle of $3...

In a broad side array of $20$ isotropic radiators, equally spaced at a distance of $\frac{\lambda}{2}$, the beam width between first nulls is$51.3$ degrees$11.46$ degrees...

In a multicavity magnetron, strapping is employed primarilyto prevent mode jumpingto increase the separation between the resonant frequencies in the $\pi$-mode and in the...

The beamwidth-between-first null of uniform linear array of $\mathrm{N}$ equally-spaced (element spacing $=d$ ), equally-excited antennas is determined by$\mathrm{N}$ alo...

Two dissimilar antennas having their maximum directivities equal,must have their beamwidths also equalcannot have their beamwidths equal because they are dissimilar anten...

Which of the following statements is/are correct?All the resonant frequencies of a microwave cavity are harmonics of a single frequencyNo two of the resonant frequencies ...

Although a laser beam is highly directional, its beam width increases with propagation. This increase is due tocoherencediffractionpolarizationinterference

At $20 \; \mathrm{GHz}$, the gain of a parabolic dish antenna of $1$ meter diameter and $70 \%$ efficiency is$15 \mathrm{~dB}$$25 \mathrm{~dB}$$35 \mathrm{~dB}$$45 \mathr...

In the design of a single mode step index optical fiber close to upper cut-off, the single-mode operation is $\text{NOT}$ preserved ifradius as well as operating waveleng...

A rectangular waveguide of internal dimensions ( $\mathrm{a}=4 \mathrm{~cm}$ and $\mathrm{b}=3 \mathrm{~cm}$ ) is to be operated in $\mathrm{TE}_{11}$ mode. The minimum o...

The interior of a $\frac{20}{3} \mathrm{~cm} \times \frac{20}{4} \mathrm{~cm}$ rectangular wave guide is completely filled with a dielectric of $\varepsilon_{r}=4$. Waves...

For a dipole antennathe radiation intensity is maximum along the normal to the dipole axisthe current distribution along its length is uniform irrespective of the lengtht...

A rectangular waveguide having $\mathrm{TE}_{10}$ mode as dominant mode is having a cutoff frequency of $18-\mathrm{GHz}$ for the $\mathrm{TE}_{w,}$ mode. The inner broad...

A metal sphere with $1 \mathrm{~m}$ radius and a surface charge density of $10 \; \mathrm{Coulombs / m}^{2}$ is enclosed in a cube of $10 \mathrm{~m}$ side. The total out...