Quiz Electronics Engineering 20 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 20/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. Which of the following analog modulation scheme requires the minimum transmitted power and minimum channel band-width?
(a) SSB
(b) DSB-SC
(c) VSB
(d) AM

Q2. A microprocessor is called an ‘n-bit microprocessor’ depending on –
(a) register length
(b) size of internal data bus
(c) size of external data bus
(d) None of these

Q3. Two charge are placed at a small distance apart. If a glass slab is placed between them, the force between the charges will
(a) not change
(b) increase
(c) decrease
(d) reduces to zero.

Q4. Assertion(A): The stability of the system is assured if the Region of Convergence(ROC) includes the unit circle in the z-plane.
Reason(R): For a causal stable system all the poles should be outside the unit circle in the z-plane.
(a) Both A and R are True and R is the correct explanation of A.
(b) Both A and R are True but R is not the correct explanation of A.
(c) A is True but R is False.
(d) A is False but R is True.

Q5. If x and y are Boolean variables, which one of the following is the equivalent of x ⊕ y ⊕ xy.
(a) x + y ̅
(b) x + y
(c) 0
(d) 1

Q6. If a parallel resonant circuit is shunted by a resistance then
(a) circuit impedance is decreased
(b) the gain of the circuit is increased
(c) ‘Q’ of the circuit is increased
(d) None of these

Q7. The final value theorem is
(a) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →0 )⁡〖(〖z-1)〗^(-1) 〗 X^+(z^(-1))
(b) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →1 )⁡〖X^+ 〗(z)
(c) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →0 )⁡〖(z^(-1))〗 X^+(z)
(d) lim┬(k →∞ )⁡〖x(k)〗 = lim┬(z →1 )⁡〖(z-1)〗 X^+(z)

Q8. Match List-I with List-II and select the correct answer using codes given below the lists:
List-I
A. At peak point
B. At Valley point
C. Reverse bias region
D. Beyond valley point
List-II
1. Low tunnelling current
2. Zero tunnelling current
3. High diffusion current
4. High tunnelling current
Codes:
A B C D
(a) 3 2 4 1
(b) 1 2 4 3
(c) 3 4 2 1
(d) 1 4 2 3

Q9. Compact disk is which type of memory?
(a) Primary Memory
(b) RAM
(c) ROM
(d) Secondary Memory

Q10. An electric charge of Q coulombs is located at the origin. Consider electric potential V and electric field intensity E at any point (x, y, z). Then
(a) E is a vector and V is a scalar.
(b) E and V both are vectors.
(c) E is a scalar and V is a vector.
(d) E and V both are scalars.

SOLUTIONS

S1. Ans.(a)
Sol. The bandwidth of SSB signal is minimum as compared to all other modulation scheme mentioned above. So, Channel bandwidth is minimum. It also requires minimum transmitted power.

S2. Ans.(b)
Sol. ‘n-bit microprocessor’ means microprocessor consists of n-bit internal data bus. So, it depends upon the size of internal data bus.

S3. Ans.(c)
Sol. From Coulomb’s law, we get
F = (Q_1 Q_2)/(4πε_0 ε_r r^2 )
For glass slab, ε_r > 1
As denominator increases, so final value decreases.
Hence, the force between the charges will decrease between two charges.

S4. Ans.(c)
Sol. For a causal system all the poles should lie inside the unit circle in z-plane.

S5. Ans.(b)
Sol.
f=x ⊕(y ⊕xy)
=x ⊕[y.(xy) ̅+xy.y ̅ ]
= x ⊕[y.(x ̅+y ̅)+xy.y ̅ ] [ (xy) ̅ = x ̅+y ̅ & y.y ̅ = 0]
=x ⊕[y (x ̅+y ̅ )]
=x ⊕[y x ̅ + yy ̅]
=x ⊕y x ̅
=xy ̅+x+yx ̅
= x(y ̅ + 1) + yx ̅
= x + yx ̅ = (x + x ̅)(x + y) [By boolean algebra property]
= x + y
Therefore, the equivalent of x ⊕ y ⊕ xy is (x + y).

S6. Ans.(a)
Sol. Net impedance,
Z = √(R ² +X² )
where,
R = resistance of circuit
X = reactance of circuit
When parallel resonant circuit is shunted by a resistance then reactance of the circuit decreases hence circuit impedance is decreased.

S7. Ans.(d)

S8. Ans.(b)

S9. Ans.(d)
Sol.
Primary Memory consists of Cache, RAM, Registers.
Secondary Memory consists of CD, DVD, Hard Disk, Pen Drive, Magnetic Tapes etc.

S10. Ans.(a)
Sol. Electric potential is a scalar quantity always and Electric Field is a vector quantity always.