Electronics and Communication Engineering - Exam Questions Papers

21. 

The distance between target and radar is reduced to half. Power received increases by

A. 1/16
B. 1/4
C. 4 times
D. 16 times

Answer: Option D

Explanation:

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22. 

The Causal system given below is __________
H(z) = 6 + z-1 - z-2

A. maximum phase
B. minimum phase
C. mixed phase
D. none of these

Answer: Option B

Explanation:

Minimum phase

H(z) = 6 + z-1 - z-1

6z2 + z - 1 = 0

We have zeros at z = 1/3 and z = - 1/2

All the zeroes lies inside the unit circle, it is a min. phase system.


23. 

Given potential sin Θ cos Φ, find flux density D at (2, 2p, 0)

A. 22.12 pC/m2
B. 2.212 pC/m2
C. 22.12 nC/m2
D. 2.212 nC/m2

Answer: Option A

Explanation:

Now E = -∇V

E = ∇V

At r = 2, θ = p/2; Φ = 0 we have

D = 22.12 PC/m2.


24. 

The following circuit is implementation of

  1. Sum of full adder
  2. Carry of half adder
  3. Difference of full subtractor

A. (i) only
B. (iii) only
C. (ii) only
D. (i) and (ii)

Answer: Option D

Explanation:

Now it is evident from the truth tables that sum and differennce are same.


25. 

The Thevenin impedance Zth between the nodes P and Q in the following circuit is

A. 1
B.
C.
D.

Answer: Option A

Explanation:

For finding Thevenin equivalent

Short voltage source

Open circuit source

Now Thevenin equivalent

.