ECIL Placement Paper

Company: Electronics Corporation of India Limited

91. The electric field component of a uniform plane wave propagating in a lossless magnetic dielectric medium is given by E(t,z)=ax 5cos(10^9 t – 20/3 z)V/m. If η0 represents the intrinsic impedance of the free space, the corresponding magnetic field component is given by

a) H(t,z)= ay 5/2 η0 cos(10^9t – 20/3 z)A/m

b) H(t,z)= ay 10/ η0 cos(10^9t – 20/3 z)A/m

c) H(t,z)= az 5/2 η0 cos(10^9t – 20/3 z)A/m

d) H(t,z)= az 10/ η0 cos(10^9t – 20/3 z)A/m

92. The skin depth of a non‐magnetic conducting material at 100 MHz is 0.15 mm. The distance which a plane wave of frequency 10 GHz travels in this material before its amplitude reduces by a factor of e^‐1 is

a) 0.0015 mm

b) 0.015 mm

c) 0.15 mm

d) 1.5 mm

93. A lossless transmission line has a characteristic impedance of 100 ohms and an inductance per unit length of 1 μH/m. If the line is operated at 1 GHz, the propagation constant β is

94. When a load resistance Rl is connected to a lossless transmission line of characteristic impedance 75 ohms, it results in a VSWR of 2. The load resistance is

a) 100 ohms

b) 75√2 ohms

c) 120 ohms

d) 150 ohms

95. A two‐port network characterized by the S‐parameter matrix, [S] = [0.3 L0 0.9 L90 0.9 L90 0.2 L0] Is

a) both reciprocal and lossless

b) reciprocal, but not lossless

c) lossless, but not reciprocal

d) neither reciprocal nor lossless

96. A lossless air filled rectangular waveguide has internal dimensions of a cm * b cm. If a=2b and the cutoff frequency of the TE02 mode is 12 GHz, the cutoff frequency of the dominant mode is

a) 1 GHz

b) 3 GHz

c) 6 GHz

d) 9 GHz

97. A Hertzian dipole antenna is placed at the origin of a coordinate system and it is oriented along z‐axis. In which one of the following planes the radiation pattern of the antenna has a circular shape?

a) x=0

b) y=0

c) z=0

d) ø=45

98. Which one of the following statements is not true?

a) Antenna losses are taken into account in calculating its power gain

b) For an antenna which does not dissipate any power, the directive gain and the power gain are equal
c) Directivity of an antenna is the maximum value of its directive gain

d) The directive gain of a Hertzian dipole is same in all direction

99. The directivity of a half dipole antenna is

a) 1.0

b) 1.5

c) 1.64

d) 2

100. Which one of the following is not true for a step index optical fibre?

a) It can support multiple modes

b) HE11 mode is its lowest order mode

c) The refractive index of the cladding is higher than that of the core

d) At a given wavelength, single mode operation is possible by proper choice of core diameter, core and cladding refractive indices.

ECIL Placement Paper

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