1

GATE ECE 2017 Set 2

Numerical

+2

-0

The permittivity of water at optical frequencies is $$1.75{\varepsilon _0}$$. It is found that an isotropic light source at a distance d under water forms an illuminated circular area of radius $$5m$$, as shown in the figure. The critical angle is $${\theta _c}$$

The value of $$d$$ (in meter) is ______ .

Your input ____

2

GATE ECE 2017 Set 1

Numerical

+2

-0

An optical fiber is kept along the$$\widehat Z$$ direction. The refractive indices for the electric fields
along $$\widehat X$$ and $$\widehat Y$$ directions in the fiber are $${n_x} = 1.5000$$ and $${n_y} = 1.5001$$, respectively ($${n_x} \ne {n_y}$$ due to the imperfection in the fiber cross-section). The free space wavelength of a light wave propagating in the fiber is $$1.5\,\,\,\mu m$$. If the light wave is circularly polarized at the input of the fiber, the minimum propagation distance after which it becomes linearly polarized, in centimeters, is _______ .

Your input ____

3

GATE ECE 2016 Set 3

Numerical

+2

-0

A radar operating at 5 GHz uses a common antenna for transmission and reception. The antenna has a gain of 150 and is aligned for maximum directional radiation and reception to a target 1 km away having radar cross-section of 3m

^{2}. If it transmits 100 kW, then the received power (in $$\mu W$$) is ______ .Your input ____

Questions Asked from Miscellaneous (Marks 2)

Number in Brackets after Paper Indicates No. of Questions

GATE ECE Subjects

Signals and Systems

Representation of Continuous Time Signal Fourier Series Discrete Time Signal Fourier Series Fourier Transform Discrete Time Signal Z Transform Continuous Time Linear Invariant System Transmission of Signal Through Continuous Time LTI Systems Discrete Time Linear Time Invariant Systems Sampling Continuous Time Signal Laplace Transform Discrete Fourier Transform and Fast Fourier Transform Transmission of Signal Through Discrete Time Lti Systems Miscellaneous Fourier Transform

Network Theory

Control Systems

Digital Circuits

General Aptitude

Electronic Devices and VLSI

Analog Circuits

Engineering Mathematics

Microprocessors

Communications

Electromagnetics