Quiz Electronics Engineering 4 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 04/09/2020

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

Q1. The energy gap between valance band and conduction band is
(a) 1 eV
(b) 7 eV
(c) 0.1 eV
(d) 0.7 eV

Q2. Poisson’s equation is derived with the following assumption about the medium. The medium is
(a) Non-homogeneous and isotropic
(b) Non-homogeneous and non-isotropic
(c) homogeneous and non-isotropic
(d) homogeneous and isotropic

Q3. To multiply a number by 8 in 8085 we have to use RAL instruction –
(a) Once
(b) Twice
(c) Thrice
(d) Four times

Q4. The diagonal clipping in Amplitude Modulation(using Envelope detector) can be avoided if RC time constant of the envelope detector satisfies the following condition, (here W is the message bandwidth and ω is carrier frequency both in rad/sec)
(a) RC = 1/ω
(b) RC > 1/W
(c) RC < 1/ω
(d) RC < 1/W

Q5. The value of current at resonance in series RLC circuit is affected by the value of
(a) R
(b) L
(c) C
(d) none of the above

Q6. The function of presentation layer is to __________.
(a) Validate and establish connection
(b) Encrypt data
(c) Close the session
(d) Flow Control

Q7. The covariance function of a band limited white noise is
(a) A Dirac delta function
(b) An exponentially decreasing function
(c) a sinc function
(d) a sinc^2 function

Q8. In Boolean algebra, (X+ Y).(X+Z) is equal to
(a) X+YZ
(b) Y+XZ
(c) XY+Z
(d) XZ+Y

Q9. Consider the following:
1. Electric current flowing in a conducting wire.
2. A moving charged belt.
3. An electron beam in a cathode ray tube.
4. Electron movement in a vacuum tube.
Which of the above are examples of convection current?
(a) 1, 2, 3 and 4
(b) 1, 2 and 4
(c) 1 and 3
(d) 2, 3 and 4

Q10. Microprogramming refers to
(a) the use of storage to implement the control unit
(b) programming at micro level
(c) emulation
(d) array processing

SOLUTIONS

S1. Ans.(a)
Sol. A semiconductor material has almost filled valence band and nearly empty conduction band with a very small energy gap (≃ 1 eV) between them.

S2. Ans.(d)

S3. Ans.(c)
Sol. ‘RAL’ means each binary bit of the accumulator is rotated left by one position through the carry flag. The D_7 bit data is placed in carry flag and data of carry flag is placed in D_0 bit.
In 8085 microprocessor, to multiply any number by 8 we have to use RAL instruction thrice.

S4. Ans.(d)
Sol. For proper envelope detection and to avoid diagonal clipping, RLC should be
1/f_c < RLC < 1/f_m
Therefore, 1/ω < RC < 1/W

S5. Ans (a)
Sol. At resonance, the net reactance is zero. The reactance effect of both inductor and capacitor is cancelled out. So, net impedance is resistive only. Hence, The value of current at resonance in series RLC circuit is due to resistance only.
Current(I) = V/R

S6. Ans.(b)
Sol. The Presentation layer is present at the sixth position in the OSI(Open Systems Interconnection) model. It helps the application layer in delivery and formatting of information for further processing or display. It does all the work related to data presentation and transport, including translation, encryption, and compression.
Functions:-
Network security and confidentiality management, text compression and packaging.
Syntax conversion, code conversion, character conversion, data format modification, data compression, encryption.
Grammar negotiation
Connection management

S7. Ans.(c)
Sol. Band limited noise is a rectangular function. So, covariance function is a sinc function.

S8. Ans.(a)
Sol. Expansion Rule is
(X+ Y)(X + Z) = XX+ XZ + XY + YZ [XX = X]
= X(1+Z) + XY+ YZ = X + XY + YZ [1+Z=1 X.1= X]
= X(1 + Y) + YZ = X+ YZ

S9. Ans.(d)
Sol.
A convection current is a process which involves the movement of energy from one place to another.
Conduction current is the electric current which exists in a conductor when the electrons flow in the conductor at a uniform rate.

S10. Ans.(c)
Sol. Microprogramming consists of microcode with the help of which large number of architectures are achieved. It consists of large number of execution units and wider word lengths.

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