Q. Calculate the critical frequency for the E layer if maximum ionic densities are 3 x 10⁶

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Q. A uniform plane wave travelling in air is incident on the plane boundary between air and another dielectric medium with εr = 4. The reflection coefficient for the normal incidence is

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Q. A transmission line has characteristics impedance of (75 + j 0.01) Ω and is terminated in a load impedance of (70 + j 50) Ω. The transmission coefficient will be

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Q. Maximum effective aperture of an antenna which is operating at a wavelength of 3 meters and has a directivity of 100

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Q. The distance between maxima and minima of a standing wave is

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Q. A TV. transmitting aerial is fixed on top of a 150 metre tower located on a mountain 1200 m height. The range of transmitter is

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Q. A 10 GHz signal propagates in a waveguide with a phase velocity of 4 x 10⁸ m/s. If the signal produces standing wave in the guide, then the distance between successive minimal will be

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Q. The incidence from dielectric medium 1 (ε1) into dielectric medium 2 (ε2), Brewster angle θB and the corresponding angle of transmission θt for ε2/ε1 = 3 will be respectively

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Q. A medium of relative permittivity εr2 = 2 forms an interface with free space. A point source of EM energy is located in the medium at a depth of 1 meter from the interface. Due to the total internal reflection, the transmitted beam has a circular cross-section over the interface. The area of the beam cross section at the interface is given by

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Q. A transmission line of characteristic impedance z0 = 50 Ω. Phase Velocity = 2 x 10⁸ m/sec, and length l = 1 m is terminated by a load z1 = (30 - j 40) ohms. The input impedance of the line for a frequency of 100 MHz will be

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Q. A circular waveguide carries TE11 mode whose radial electric-field is given by

Er = E₀J1 (r) sin φ V/m

where 'r' is the radial distance in cm, from the waveguide axis. The cut-off wavelength of the mode is

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Q. The I/P impedance of a λ/8 long short circuited section of a loss less transmission line is

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Q. For frequencies upto 1650 kHz __________ antenna is used

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Q. Due to which of the following reasons, the ground wave eventually disappears, as one moves away from the transmitter?

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Q. A loop antenna may be of

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Q. Microwave signals transmitted towards the sky are

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Q. Radiation intensity does not depend upon

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Q. Δ²V = - ρ/E is known as __________ equation

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Q. A vertical earthed antenna is resonant when its physical height is equal to

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Q. Which of the following is a vector quantity?

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