Online Electronics and Communication Engineering Test - Previous Exam Papers Test 3

Instruction:

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Total number of questions: 20.
Time allotted: 30 minutes.
Each question carries 1 mark; there are no negative marks.
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Z = __________

C[A(B + C) + D]

(AB + AC + D)

(CA + AC + D)

none of these

[#]

A point charge of 6 μC is located at the origin, uniform line charge density of 180 nC/m of 8 m length lies along the x axis and a uniform sheet of charge equal to 25 nC/m² of area p x 4² lies in the z = 0 plane. Calculate total electric flux leaving the surface of sphere of 4 m radius centered at origin.

86.97 μC

8.697 nC

8.697 μC

86.97 nC

[#]

The following circuit is implementation of:

sum of full adder
carry of half adder
difference of full subtractor

1 only

3 only

2 only

1 and 2 both

[#]

The probability density function of a random variable x is as shown.

The mean of the distribution is:

[#]

With respect to the following 555 timer circuit what will be the value of R_A and R such that the LED turns on for a duration of 10 ms every time it receives negative trigger pulse. LED operating current = 20 mA, V_f = 1.4 V, Vo _on = 13.4 V and C = 0.22 nf

41.4 KΩ, 600 Ω

45 KΩ, 630 Ω

43.5 KΩ, 580 Ω

44.9 KΩ, 600 Ω

[#]

Given f = GEF + KHIJ + LMON + TUVWXYZ and

E + F + G = LMN
V + W = U . Z . Y . X . T
NAND B
(UVW ⊕ WVU) = KJ(XY ⊕ XY)

Then f is equivalent to

EF + UZ + HI

None of these

[#]

The value of the integral of the function g(x, y) = 4x³ + 10y⁴ along the straight line segment from the point (0, 0) to the point (1, 2) in the x-y plane is

[#]

The eigen values of a skew symmetric matrix are

always zero

always pure imaginary

either zero or pure imaginary

always real

[#]

The circuit shown in the figure has 4 boxes each described by inputs P, Q, R and outputs Y, Z with
Y = P ⊕ Q ⊕ R, Z = RQ + P R + Q P

The circuit is a

4 bit adder giving P + Q

4 bit subtractor giving P - Q

4 bit subtractor giving Q - P

4 bit adder giving P + Q + R

[#]

10.

A switch tail ring counter is made by using a single D FF. The resulting circuit is a

SR FF

JK FF

D FF

T FF

[#]

11.

A transmitter radiates a power 20 KW and its base current is 18A. The radiation resistance of the antenna is

1111 Ω

900 Ω

75 Ω

62 Ω

[#]

12.

The Thevenin resistance of the circuit is

3 K

[#]

13.

Assertion (A): The small signal analysis of a transistor amplifier is done to obtain the current gain, voltage gain and the conversion efficiency of an amplifier.

Reason (R): The small signal analysis of a transistor amplifier uses the small signal parameters of the transistor.

Both A and R are individually true and R is the correct explanation of A

Both A and R are individually true but R is not the correct explanation of A

A is true but R is false

A is false but R is true

[#]

14.

Consider the following, logic diagram :

The count sequence of the above logic diagram is :

0000 to 1111

0000 to 1001

0000 to 1010

1001 to 0000

[#]

15.

Which one of the following driving point functions does not represent an LC network?

[#]

16.

The pre-emphasis in FM aids in providing extra noise immunity by

emphasizing only the higher frequency components

emphasizing the entire frequency band

emphasizing only the lower frequency band

cutting down the low frequency noise

[#]

17.

Which of the following factors are responsible to design IC logic gates to operated at a fixed supply voltage of 5 volts?

Low heating of IC logic gates
Compatibility with other logic gates
Satisfactory and safe operation
Standardization from IC manufacturing point of view.

Select the correct answer from the codes given below:

1 only

2 only

2 and 3

3 and 4

[#]

18.

Which of the following circuits come under the class of sequential logic circuits?

Full adder
Full subtractor
Half adder
J-K flip-flop
Counter

Select the correct answer from the codes given below:

1 and 2

1, 2 and 3

3 and 4

4 and 5

[#]

19.

For the circuit shown in the given figure, assuming ideal op-amps, the output corresponding to the given input will be :

[#]

20.

Step responses of a set of three second-order underdamped systems all have the same percentage overshoot. Which of the following diagrams represents the pole of the three systems?