Electronics and Communication Gate 2014 Set-3 Questions with Answer

Ques 27 GATE 2014 SET-3


A region shown below contains a perfect conducting half-space and air. The surface current Ks on the surface of the perfect conductor is Ks = x̂2 amperes per meter. The tangential H field in the air just above the perfect conductor is

A

(x̂ + ẑ)2 amperes per meter

B

x̂2 amperes per meter

C

−ẑ2 amperes per meter

D

ẑ2 amperes per meter


(d) is the correct answer.

Ques 28 GATE 2014 SET-3


Assume that a plane wave in air with an electric field E(t) = ây10 cos(ωt − 3x − √3z) V/m is incident on a non-magnetic dielectric slab of relative permittivity 3 which covers the region z > 0. The angle of transmission in the dielectric slab is ________ degrees.


(30) is the correct answer.

Ques 29 GATE 2014 SET-3


In MOSFET fabrication, the channel length is defined during the process of

A

isolation oxide growth

B

channel stop implantation

C

poly-silicon gate patterning

D

lithography step leading to the contact pads


(c) is the correct answer.

Ques 30 GATE 2014 SET-3


A thin P-type silicon sample is uniformly illuminated with light which generates excess carriers. The recombination rate is directly proportional to

A

the minority carrier mobility

B

the minority carrier recombination lifetime

C

the majority carrier concentration

D

the excess minority carrier concentration


(d) is the correct answer.

Ques 31 GATE 2014 SET-3


At T = 300 K, the hole mobility of a semiconductor μp = 500 cm2/V-s and kT/q = 26 mV. The hole diffusion constant Dp in cm2/s is ________


(13) is the correct answer.

Ques 32 GATE 2014 SET-3


The donor and accepter impurities in an abrupt junction silicon diode are 1 × 1016 cm−3 and 5 × 1018 cm−3, respectively. Assume that the intrinsic carrier concentration in silicon ni = 1.5 × 1010 cm−3 at 300 K, kT/q = 26 mV and the permittivity of silicon εsi = 1.04 × 10−12 F/cm. The built-in potential and the depletion width of the diode under thermal equilibrium conditions, respectively, are

A

0.7 V and 1 × 10−4 cm

B

0.86 V and 1 × 10−4 cm

C

0.7 V and 3.3 × 10−5 cm

D

0.86 V and 3.3 × 10−5 cm


(d) is the correct answer.

Ques 33 GATE 2014 SET-3


The slope of the ID vs. VGS curve of an n-channel MOSFET in linear regime is 10−3 Ω−1 at VDS = 0.1 V. For the same device, neglecting channel length modulation, the slope of the √ID vs. VGS curve (in √A/V) under saturation regime is approximately _________.


(0.07) is the correct answer.

Ques 34 GATE 2014 SET-3


An ideal MOS capacitor has boron doping-concentration of 1015 cm−3 in the substrate. When a gate voltage is applied, a depletion region of width 0.5 μm is formed with a surface (channel) potential of 0.2 V. Given that ε0 = 8.854 × 10−14 F/cm and the relative permittivities of silicon and silicon dioxide are 12 and 4, respectively, the peak electric field (in V/μm) in the oxide region is _____________.


(2.4) is the correct answer.

Ques 35 GATE 2014 SET-3


The maximum value of the function f(x) = ln(1 + x) − x (where x > −1) occurs at x = ______.


(0) is the correct answer.

Ques 36 GATE 2014 SET-3


Which ONE of the following is a linear non-homogeneous differential equation, where x and y are the independent and dependent variables respectively?

A

dy/dx + xy = e−x

B

dy/dx + xy = 0

C

dy/dx + xy = e−y

D

dy/dx + e−y = 0


(a) is the correct answer.

Ques 37 GATE 2014 SET-3


Match the application to appropriate numerical method.
P1: Numerical integration → M1: Newton-Raphson Method
P2: Solution to a transcendental equation → M2: Runge-Kutta Method
P3: Solution to a system of linear equations → M3: Simpson's 1/3-rule
P4: Solution to a differential equation → M4: Gauss Elimination Method

A

P1—M3, P2—M2, P3—M4, P4—M1

B

P1—M3, P2—M1, P3—M4, P4—M2

C

P1—M4, P2—M1, P3—M3, P4—M2

D

P1—M2, P2—M1, P3—M3, P4—M4


(b) is the correct answer.

Ques 38 GATE 2014 SET-3


An unbiased coin is tossed an infinite number of times. The probability that the fourth head appears at the tenth toss is

A

0.067

B

0.073

C

0.082

D

0.091


(c) is the correct answer.

Ques 39 GATE 2014 SET-3


If z = ln(xy), then

A

x(∂z/∂x) + y(∂z/∂y) = 0

B

y(∂z/∂x) = x(∂z/∂y)

C

x(∂z/∂x) = y(∂z/∂y)

D

y(∂z/∂x) + x(∂z/∂y) = 0


(c) is the correct answer.

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