Electronics And Communication Engineering (EC) : Mock Test 2 For GATE


65 Questions MCQ Test Mock Tests Electronics & Communication Engineering GATE 2020 | Electronics And Communication Engineering (EC) : Mock Test 2 For GATE


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This mock test of Electronics And Communication Engineering (EC) : Mock Test 2 For GATE for Electronics and Communication Engineering (ECE) helps you for every Electronics and Communication Engineering (ECE) entrance exam. This contains 65 Multiple Choice Questions for Electronics and Communication Engineering (ECE) Electronics And Communication Engineering (EC) : Mock Test 2 For GATE (mcq) to study with solutions a complete question bank. The solved questions answers in this Electronics And Communication Engineering (EC) : Mock Test 2 For GATE quiz give you a good mix of easy questions and tough questions. Electronics and Communication Engineering (ECE) students definitely take this Electronics And Communication Engineering (EC) : Mock Test 2 For GATE exercise for a better result in the exam. You can find other Electronics And Communication Engineering (EC) : Mock Test 2 For GATE extra questions, long questions & short questions for Electronics and Communication Engineering (ECE) on EduRev as well by searching above.
QUESTION: 1

“Wanted a two bedroom flat in the court area for immediate possession” - An Advertisement.
Assumptions:
I. Flats are available in the court area
II. Some people will respond to the advertisement
III. It is a practice to give such an advertisement

Solution:
QUESTION: 2

Which of the following is most similar in meaning to the given word
DIRE

Solution:
QUESTION: 3

In the question given below, the sentence has a part printed in bold. That part may contain a grammatical error. Replace that part with four choices given below:

The famous playwright has been in the sick bed from the last one week.

Solution:
QUESTION: 4
He always _________ you in his letters
Solution:
QUESTION: 5
His health ____________ under the pressure of work.
Solution:
QUESTION: 6
A, B and C shoots to hit a target. If A hits the target 4 times in 5 trials, B hits in 3 times in 4 trials and C hits it 2 times in 3 trials. What is the probability that the target is hit by at least 2 persons?
Solution: Probability that A hits the target = 4/5
Probability that B hits the target = 3/4
Probability that C hits the target = 2/3
P (at least 2) = P(2) + P(3)
QUESTION: 7
Two liquids are mixed in the ratio 4:3 and the mixture is sold at Rs 20 with a profit of   %. If the first liquid is costlier than the second by Rs 7. Find the sum of costs of both the liquids.
Solution: Profit = %

Cost of 1 unit of liquid 1 = x+7
Cost of 1 unit of liquid 2 = x
(x+7)×4+3x = 15(4+3)
x = 11
x+7 = 18
Total value of the prices = 11+18 = 29
QUESTION: 8
Henry and Ford worked together to complete a task in 10 days. Had Henry worked with half of his efficiency and Ford at 5 times of his efficiency it would have taken them to finish the job in 50% of the scheduled time. In how many days can Ford complete the job working alone?
Solution: Let henry’s one day work be x
Let ford’s one day work be y

Solving 2 equations we get, y = 1/30
Hence, Ford can complete the job working alone in 30 days
QUESTION: 9
A new flag is to be designed with six vertical stripes using some or all of the colours- yellow, green, blue and red. Then the number of ways this can be done such that no two adjacent stripes have the same colour out is:
Solution: There are 6 stripes. The stripe can be coloured in 4ways, in 3, in 3 and so on.
Thus, total number of ways = 4×3×3×3×3×3=12×81
QUESTION: 10
Find the value of
Solution:
y(y-3) = 0
y = 3
QUESTION: 11
In the given circuit determine the value of current source
Solution: V = 4i

2i = 4–v
2i = 4 – 4i
6i = 4
i = 2/3
So, v = 8/3
QUESTION: 12
If power of a signal x (t) is 6 units, then determine the power of g(t), where g (t) is given as,
g(t) = 4x (t)
Solution: Power of g(t),

= 48 + 108
= 156 units
QUESTION: 13
Which one of the following is non-periodic?
Solution: For a signal to be periodic, the signal must be define from
QUESTION: 14

The ROC of z-transform of the discrete time sequence, x(n) so that x(n) is absolutely summable

Solution:


QUESTION: 15
Consider two signals and in which is band limited to 3 kHZ and is band limited to 2KHz, determine the minimum sampling frequency of g(t) where
Solution: Convolution in time domain results multiplication in frequency domain,
So resultant signal in frequency domain is limited upto 2 KHz, i.e. = 2kHz
so,             = 2 × 2
                        = 4 KHz
QUESTION: 16
A TDM link has 30 signal channels and each channel is sampled 9000 times/sec. Each sample is represented by seven binary bits and contains an additional bit for synchronization. The total bit rate for the TDM link is:
Solution: Bit rate = 30 × 9000 (7 + 1) bits/second
= 2160 kbps
QUESTION: 17
The signal flow graph of a closed loop system is shown in the figure, where represents the disturbance in the forward path. The effect of the disturbance can be reduced by
Solution: With feedback, the output due to disturbance

Without feedback output due to disturbance is

By comparing above two equations, feedback decreases the effect of noise
If Increases, disturbance decreases, But gain also decreases. This is not desirable.
If increases, disturbance increases, since noise links with
If increases, disturbance decreases, and gain also decreases. This is desirable.
QUESTION: 18

The energy of constant-amplitude complex valued exponential sequence is __________ (where A is the constant amplitude)

Solution:

QUESTION: 19
Piecewise linear model of a diode shown in the figure

Determine the value of in the given circuit
Solution:
QUESTION: 20

Which of the following is a microwave power amplifier?

Solution:
QUESTION: 21
A carrier signal is amplitude modulated by a message signal m (t) = .If the modulation index is 0.5, then the power in USB is given by 
Solution:
QUESTION: 22
For the circuit shown in the figure assume ideal diodes with forward resistance and forward voltage drop are zero. The current through diode
Solution: In the given circuit both the diodes cannot be ON simultaneously.
In the above circuit only is ON.
So current through diode is Zero.
QUESTION: 23
Determine the value of in the given circuit given = 100
 
Solution:
Since is negative, so Transistor is in cut-off mode, therefore, = 0
and = 10V and =0
Therefore
= 10 volt
QUESTION: 24
Determine the value of in the circuit, assume op-amp is ideal.
Solution:
= 11–10
= 1 volt
QUESTION: 25
Assume the op-amp is ideal the transfer characteristics of the circuit is
Solution: In the given circuit for positive half cycle of input voltage is at  i.e. –10V and diode is off,and during negative half cycle is at  i.e. +10V, so diode is ON and,virtual short-cirucit exist.
Therefore, 
So transfer characteristic
QUESTION: 26
If cross-sectional area of base-emitter junction of transistor is 2 times of transistor then determine the value of Assume of both the transistors are very large
Solution:
= 4.65 mA
As the area of base-emitter junction of transistor is two times of So
QUESTION: 27
7 EH and 5 FH are XORed. The output is multiplied by 10 H. The result is
Solution: 7EH - 01111110
5FH -  01011111
XORed 0010 0001 21H
QUESTION: 28
The minimal some of products form of is
Solution:
The K-map of the above function

So, the required minimal SoP of f is
f =
QUESTION: 29
In a twin-wire transmission line in air, the adjacent voltage maxima are at 12 cm and 18 cm. The operating frequency is.
Solution: Adjacent maxima appear with a distance of

f = 2.5 GHZ
QUESTION: 30
A system has receiver noise resistance of 50W. It is connected to an antenna with an input resistance of 50W The noise figure of the system is.
Solution: The overall noise figure of the receiver is,


= 2
QUESTION: 31
For a parabolic reflector antenna with diameter of 3m, the far field pattern measurement at 10 GHz should be carried out at a distance of at least
Solution:
QUESTION: 32
The dimension of the null space of the matrix A is, where
Solution: Since order of matrix is 3 × 3 and rank of matrix is 2
So, dimension of null space = 3 – 2 = 1
QUESTION: 33
Given that x is a random variable in the range with a probability density function f(x) the value of k is
Solution:
QUESTION: 34

Solution:

The limit is in the form of
By L-hospitals rule,

 

QUESTION: 35
The value of where the contour is the unit circle traversed clockwise is
Solution:
QUESTION: 36
The circuit shown in the figure is in series resonance at a frequency rad/sec. The value of in the volts is.
Solution:
QUESTION: 37
The circuit shown in the figure contains a dependent current source between A and B terminals. The thevenin’s equivalent resistance in kW between the terminals C and D is
Solution: Thevenin’s equivalent circuit is made by connecting 1A current source at the output and short circuiting the battery.

At node A,

QUESTION: 38
Determine the average power consume by the 4W resistor in the given circuit.
Solution:
QUESTION: 39
A discrete-time x[n] is obtained by sampling an analog signal at 10 kHz. The signal x[n] is filtered by a system with impulse response h(n) = 0.5 { d [n] +d (n – 1]}. The 3 dB cut off frequency of the filter is.
Solution:
QUESTION: 40
The transfer function of a digital system is given by Where  is real.The transfer function is BIBO stable if the value of  is
Solution: Transfer function of system,

The stability of a two-pole system can be investigated by stability criteria called “Scho-cohn” stability test In this approach there are two polynomials
and  which are calculated from denominator polynomial of the transfer function. For the system to be stable,
|
These two conditions (1) and (2) are satisfied only if = 0.5 among the given options.
QUESTION: 41
The impulse response of a continuous time system is given by h (t) = d (t – 1) + d (t – 3).The value of the step response at t = 2 is

Solution: Step response = integration of impulse response

QUESTION: 42
The impulse response of an LTI system is given as,

It represents a
Solution:
Since for n < 0 or negative values of n. So, the system is non causal Also  represents a rectangular function with the representation as

This represents the characteristics of ideal low-pass filter.
QUESTION: 43

In the circuit shown below current through the resistor is shown. Voltage across 4 Ω resistor is: 

Solution:

Voltage across 5 Ω = 10 V

Thus voltage across 7 Ω = 10 V (5 Ω || 7 Ω)

QUESTION: 44
Consider the control system shown in figure with feed forward action for rejection of a measurable disturbance d(t). The value of K, for which the disturbance response at the output y(t) is zero mean, is
Solution: For r(t) = 1

For no disturbance effect

At steady state, s = 0
K = –2
QUESTION: 45
The open loop transfer function of a system is .The angles of arrival of its root loci are
Solution: Angle of arrival
QUESTION: 46
Determine the maximum value of so that transistor remains in saturation region, Given b = 100 and =0 Volt
Solution: Small signal resistance,
QUESTION: 47
The small-signal resistance offered by the n-channel MOSPET M shown in the figure below, device transconductance parameter threshold voltage= 1 V.
Solution: Small signal resistance,
QUESTION: 48
Assuming op-amp is ideal, the magnitude of the transfer impedance in of the current to voltage converter in the given circui
Solution: Apply KVL at node A,

QUESTION: 49
Assuming the op-amp is ideal, the input impedance that is seen by the voltage source in the given circuit is.
Solution:
QUESTION: 50
A n junction has a built-in potential of 0.6 V. The width of depletion layer at a reverse bias voltage of 1.4 V is 4µm. For a reverse bias of 17.4 V the depletion layer width will be
Solution:
QUESTION: 51
For the circuit shown below determine the ac voltage across the diode, given = 26 mV,0.7 V and h = 1 and C is very large
Solution:

and for ac analysis replace diode by its dynamic resistance

QUESTION: 52
Integrated output waveform for the dual slope ADC is shown in the figure. The time for an 10 bit counter with 5 mHZ clock will be.
Solution:
QUESTION: 53
In figure, if the input A = 0 and B = 0, the output F can be mode 0 by making
Solution:
Given, A = 0, and B = 0
So only C = 1 and D = 1 will give output 0
Y = 0
QUESTION: 54
The initial state of the counter in the circuit shown below is 01, and resolution of DAC is 0.5 volt. Determine the output of DAC after three clock pulses.
Solution: The state diagram of counter

So, output of DAC = 0 volt
QUESTION: 55
A full duplex binary FSK transmission is made through a channel of bandwidth of 20 KHZ.In each direction of transmission the two carriers used for the two states are separated by 6KHZ. The maximum baud rate for this transmission is.
Solution: Since the transmission is full duplex 10 KHz will be allocated for each direction
Bandwidth = Band Rate + ()
Given = 6 KHz
So, Band Rate = Band width - ()
= 10 KHz – 6
= 4000 bps
QUESTION: 56
The carrier signal is angle modulated by a message signal m(t) = .The deviation constant = 1.5 rad/V. Bandwidth of the modulated signal using Carson’s rule is.
Solution:
= 2(12 + 1) × 10 KHz
= 260 KHz
QUESTION: 57
The output signal of an AM transmitter is expressed as .The ratio of power of carrier signal to power contained in single sideband is
Solution:
= 450 W
QUESTION: 58
A frequency modulator has output . Where = 100 Hz/V and m (t) is shown in the figure. According Carson’s rule the bandwidth of s(t) is
Solution:
= 500 Hz,
So Bandwidth = 2
2(500 + 200)
= 1400 Hz
QUESTION: 59
The magnetic field intensity vector of a plane wave is given by .where  denotes the unit vector in Z direction.The wave is propagating with 0 phase velocity.
Solution:
QUESTION: 60
An air-filled rectangular waveguide has inner dimensions of 5cm × 4 cm. The wave impedance of the mode of propagation in the waveguide at a frequency of 18 GHZ is
Solution:
QUESTION: 61
A load impedance 150 W is to be matched to a 600 W lossless transmission line by using a quarter wave line transformer. The characteristic impedance of the quarter wave transformer is required
Solution:
QUESTION: 62
Consider a random variable x that takes values +1 and -1 with probability 0.5 each. The value of the cumulative distribution function F (x) at x = -1 and + 1 are
Solution: The PDF of the random variable is

The cumulative distribution function F(x) is the probability upto x as given below
QUESTION: 63
If the matrix A is such that A = then the determinant of A is equal to
Solution:
QUESTION: 64
The maximum value of in the interval [1,6] is
Solution:
  = 21

= 41
So the maximum value of f(x) in interval [1, 6] is 41
QUESTION: 65
The maximum value of the solution y (t) of the differential equation with initial conditions = 0 and y(0) = 1 for 0 is
Solution:
y = A cos x + B sin x
y(0) = 1
Therefore 1 = A × 1 + B × 0
 A = 1
y = – A sin x + B cos x
= 1
1 = – A × 0 + B × 1
 B = 1
so, y = cos x + sin x

=