### GATE questions-ECE

No. Question
1 The Boolean expression AC + B
C
is equivalent to
Options
A)
A
C + B
C
+ AC B)
B
C + AC + B
C
+
A
C
B
C) AC + B
C
+
B
C + ABC D) ABC +
A
B
C
+ AB
C
+ AB
C
Your Answer (Not Answered)
Correct Answer D
2 The resistivity of a uniformly doped n-type silicon sample is 0.5 W-cm. If the electron mobility (mn) is 1250 cm2/V-sec and the charge of an electron is 1.6 x 10-19 Coulomb, the donor impurity concentration (ND) in the sample is
Options
A) 2 x 1016/cm3 B) 1 x 1016/cm3
C) 2.5 x 1015/cm3 D) 2 x 1015/cm3
Your Answer (Not Answered)
Correct Answer B
3 Consider the following statements S1 and S2.
S1: The b of a bipolar transistor reduces if the base width is increased.
S2: The b of a bipolar transistor increases if the doping concentration in the base is increased. Which one of the following is correct?
Options
A) S1 is FALSE and S2 is TRUE B) Both S1 and S2 are TRUE

C) Both S1 and S2 are FALSE D) S1 is TRUE and S2 is FALSE
Your Answer (Not Answered)
Correct Answer D
4 A system has poles at 0.01 Hz, 1 Hz and 80 Hz; zeros at 5 Hz, 100 Hz and 200 Hz. The approximate phase of the system-response at 20 Hz is

Options
A) – 90° B) 0°
C) 90° D) – 180°
Your Answer (Not Answered)
Correct Answer A
5 In an abrupt p-n junction, the doping concentrations on the p-side and n-side are NA = 9x 1016/cm3 and ND = 1 x 1016/cm3 respectively. The p-n junction is reverse biased and the total depletion width is 3 m m. The depletion width on the p-side is
Options
A) 2.7 mm B) 0.3 mm.
C) 2.25 mm D) 0.75 mm
Your Answer (Not Answered)
Correct Answer B
6 A master-slave flip-flop has the characteristic that
Options
A) change in the input immediately reflected in the output
B) change in the output occurs when the state of the master is affected
C) change in the output occurs when the state of the slave is affected
D) both the master and the slave states are affected at the same time
Your Answer (Not Answered)
Correct Answer C
7

A parallel plate air-filled capacitor has plate area of l0-4 m2 and plate separation of 10-3 m. It is connected to a 0.5 V, 3.6 GHz source. The magnitude of the displacement current is (e0 = 1/36p x 10-9 F/m)
Options
A) 10 mA B) 100 mA
C) 10 A D) 1.59 mA
Your Answer (Not Answered)
Correct Answer A
8 The phase velocity of an electromagnetic wave propagating in a hollow metallic rectangular waveguide in the TE10 mode is
Options
A) equal to its group velocity B) less than the velocity of light in free space
C) equal to the velocity of light in free space D) greater than the velocity of light in free space
Your Answer (Not Answered)
Correct Answer D
9 Noise with uniform power spectral density of N0W/Hz is passed through a filter H (w) = 2 exp(-jwtd) followed by an ideal low pass filter of bandwidth BHz. The output noise power in Watts is
Options
A) 2N0B B) 4N0B
C) eN0B D) 16 N0B
Your Answer (Not Answered)
Correct Answer B
10 The cascade amplifier is a multistage configuration of
Options
A) CC-CB B) CE-CB
C) CB-CC D) CE-CC
Your Answer (Not Answered)
Correct Answer B
11 Consider a lossless antenna with a directive gain of +6dB. If 1 mW of power is fed to it the total power radiated by the antenna will be
Options
A) 4 mW B) 1 mW
C)
7 mW D) 1/4 mW
Your Answer (Not Answered)
Correct Answer A
12 The bandgap of Silicon at room temperature is
Options
A) 1.3 eV B) 0.7 eV
C) 1.1 eV D) 1.4 eV
Your Answer (Not Answered)
Correct Answer C
13 For a signal x(t) the fourier transform is X(f). Then the inverse Fourier transform of X(3f + 2) is given by
Options
A)
1
2
x(
t
2
)e(j3p t) B)
1
3
x(
t
3
)e-j4pt/3
C) 3x(3t)e-j4p t D) x(3t+2)
Your Answer (Not Answered)
Correct Answer B
14 In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor
Options
A) 8/6 B) 12

C) 16 D) 8
Your Answer (Not Answered)
Correct Answer C
15

Match the following and choose the correct combination:

Group 1 Group 2
E. Newton-Raphson method
F. Runge-kutta method
G. Simpson,s Rule
H. Gauss elimination 1. Solving nonlinear equations
2. Solving linear simultaneous equations
3. Solving ordinary differential equations
4. Numerical integration
5. Interpolation
6. Calculation of Eigenvalues
Options
A) E-6, F-1, G-5, H-3 B) E-1, F-6, G-4, H-3
C) E-1, F-3, G-4, H-2 D) E-5, F-3, G-4, H-1
Your Answer (Not Answered)
Correct Answer C
16 The Fourier transform of a conjugate symmetric function is always
Options
A) imaginary B) conjugate anti-symmetric
C) real D) conjugate symmetric
Your Answer (Not Answered)
Correct Answer C
17

Match the following and choose the correct combination.

Group 1 Group 2
E – continuous and aperiodic signal
F – continuous and periodic signal
G – Discrete and aperiodic signal
H – Discrete and periodic signal 1 – Fourier representation is continuous and aperiodic
2 – Fourier representation is discrete and aperiodic
3 – Fourier representation is continu-ous and periodic
4 – Fourier representation is discrete and periodic
Options
A) E – 3, F – 2, G – 4, H -1 B) E -1, F – 3, G – 2, H – 4
C) E -1, F – 2, G – 3, H – 4 D) E – 2, F – 1, G – 4, H – 3
Your Answer (Not Answered)
Correct Answer C
18 A device with input x(t) and output y(t) is characterized by: y(t) = x2(t).
An FM signal with frequency deviation of 90 kHz and modulating signal bandwidth of 5 kHz is applied to this device. The bandwidth of the output signal is

Options
A) 370 kHz B) 190 kHz
C) 380kHz D) 95kHz
Your Answer (Not Answered)
Correct Answer C
19 For the polynomial P(s) = s5 + s4 + 2s3 + 2s2 + 3s + 15, the number of roots which lie in the right half of the s-plane is
Options
A) 4 B) 2
C) 3 D) 1
Your Answer (Not Answered)
Correct Answer B
20 An AM signal is detected using an envelope detector The carrier frequency and modulating signal frequency are 1 MHz and 2 kHz respectively. An appropriate value for the time constant of the envelope detector is
Options
A) 500 msec B) 20 msec
C) 0.2 msec D) 1 msec
Your Answer (Not Answered)
Correct Answer B

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#### 10 Comments

1. sudhamalar.k says:

how will prepare

2. anusha lagishetty says:

want some more ques… plzzz

3. bharathi says:

is good

4. ilakkiya says:

pls give some idea to cover the syllabus….give more qns …….. need some brief explanation about the pass percentage of the gate exam…. pls pls pls give the answer as soon as possible……

5. kani says:

some more questions

6. mohana says:

i need gate model question paper with answer in ECE BRANCH

7. mohana says:

GIVE MODEL QUES

8. shaik hafeez says:

hw 2 sucess in gate

9. jayakumarc says:

sir please send the ece question papers for gate to my id

10. amritha says:

pls.. mail me ece gate previous papers