ISRO Scientist or Engineer Electronics Dec 2017

Instructions

For the following questions answer them individually

ISRO Scientist or Engineer Electronics Dec 2017 - Question 71


In a digital circuit the set-up time violation can be fixed by

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 72


Number of J-K flip flops in modulo 16 binary up-counter are

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 73


The solid angle subtended by the sun as viewed from the earth is Ω =$$4 \times 10^{-5}$$ steradian.
A microwave antenna designed to be used for studying the microwave radiation from the
sun has a very narrow beam whose equivalent solid angle is approximately equal to that
subtended by the sun. What is the approximate directivity, D?

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 74


A gain-standard horn is known to have a gain G = 10. It is being used to measure the gain of a large directional antenna by the comparison method. When the antenna being measured is connected to the receiver it is found to be necessary to insert an attenuator adjusted to attenuate by 23 dB in order to have the same receiver output that was observed with the horn connected. What is the gain of the large antenna?

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 75


A paraboloidal-reflector antenna is designed for operation at 3 GHz. Its largest aperture dimension is 20 feet. It is desired to build a scale model of this antenna with the largest aperture dimension scaled to 18 inches. At what frequency must this model be operated in order to have the same pattern as the full-size antenna?

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 76


An antenna has a radiation resistance of 72 Ω ,a loss resistance of 8 Ω and power gain of 16.Calculate its directivity.

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 77


The current density at the surface of a thick metal plate is 100 $$\frac{A}{m^{2}}$$ What is the skin depth if the current density at a depth of 0.0059 cm is 0.272 $$\frac{A}{m^{2}}$$?

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 78


An air filled rectangular waveguide $$R_{1}$$ is operating at the frequency 2 GHz and another air filled rectangular waveguide $$R_{2}$$ is operating at 4 GHz. The guide wavelengths of these waveguides at their respective frequencies are equal. If the cut-off frequency of waveguide $$R_{1}$$ is 1 GHz, what is the cut-off frequency of the waveguide $$R_{2}$$ in GHz?

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 79


An electromagnetic wave propagates through a lossless insulator with a velocity $$1.5 \times 10^{10} \frac{cm}{s}$$ . Calculate the electric and magnetic properties of the insulator if its intrinsic impedance is 90 $$\pi$$ ohms

Video Solution

ISRO Scientist or Engineer Electronics Dec 2017 - Question 80


A square waveguide carries $$TE_{11}$$ mode whose axial magnetic field is given by $$H_{Z}=H_{o} \times \cos (\frac{\pi x}{\sqrt{8}}) \times \cos (\frac{\pi y}{\sqrt{8}})$$ A/m where waveguide dimensions are in cm. What is the cut-off frequency of the mode?

Video Solution
cracku

Boost your Prep!

Download App