Quiz Electronics Engineering 28 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 28/09/2020

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

Q1. The line code that has zero dc component for pulse transmission of random binary data is
(a) non-return to zero (NRZ)
(b) return to zero (RN)
(c) alternate mark inversion (AM)
(d) none of the above

Q2. Which one of the statements is correct?
On a conducting surface boundary, electric field lines are
(a) always tangential
(b) always normal
(c) neither tangential nor normal
(d) at an angle depending on the field intensity

Q3. In a full wave rectifier circuit using centre tapped transformer, the peak voltage across half of the secondary winding is 30 V. Then PIV is:
(a) 30 V
(b) 10 V
(c) 15 V
(d) 60 V

Q4. When bundle conductor are used in place of single conductance the effective inductance and capacitance will respectively
(a) increase and decrease
(b) decrease and increase
(c) decrease and remain unaffected
(d) remain unaffected and increase

Q5. Identify the incorrect statement regarding FTP.
(a) FTP sends its control information in-band
(b) FTP uses two parallel TCP connections
(c) FTP stands for File Transfer Protocol
(d) FTP sends exactly one file over the data connection

Q6. How many bits are required to store one BCD digit?
(a) 1
(b) 2
(c) 3
(d) 4

Q7. A real signal x(f) has fourier transform X(f). Which one of the following is correct?
(a) Both magnitude and phase of X(f) have even symmetry
(b) Magnitude of X(f) has odd symmetry while phase of X(f) has even symmetry
(c) Magnitude of X(f) has even symmetry while phase of X(f) has odd symmetry
(d) Both magnitude and phase of X(f) have odd symmetry

Q8. A coil of resistance of 5 Ω and inductance 0.4 H is connected to a 50 V d.c. supply. The energy stored in the field is
(a) 20 Joules
(b) 10 Joules
(c) 40 Joules
(d) 80 Joules

Q9. The advantage of write(copy) back data cache organization is
(a) write allocate on write miss
(b) less memory bandwidth requirement
(c) Main memory consistency
(d) higher capacity

Q10. In _________ systems, resources are allocated on demand.
(a) line switching
(b) circuit switching
(c) packet switching
(d) frequency switching

SOLUTIONS

S1. Ans.(c)
Sol. There are two types coding:-
Source coding techniques are used in PCM and DM for converting analog signal to digital i.e., train of binary digits.
Line coding converts stream of binary digits into a formal code. It is used for data transmission of a digital signal over a transmission line. This process is chosen to avoid overlap and distortion of signal such as Inter-Symbol Interference.
AMI(Alternate Mark Inversion) is a synchronous clock encoding technique. It uses bipolar pulses to represent logical 1 values and a logical 0 is represented by no symbol. So, It is a three level system. This code has zero dc component for pulse transmission of random binary data.

S2. Ans.(b)
Sol. On a conducting surface boundary, the tangential component of the Electric field is zero. It is absorbed by the conducting surface. Only normal component of the Electric Field exist.

S3. Ans. (d)
Sol. In full wave circuit using centre tapped transformer PIV = 2V_m.
So, PIV = 2 × 30 = 60 V

S4. Ans.(b)
Sol. Bundled conductor are used for reducing corona loss and radio interference because it reduces voltage gradient. Hence, bundled conductors have higher capacitance and lower value of inductive reactance.

S5. Ans.(a)
Sol. FTP(File Transfer Protocol) is an application layer protocol which moves files between local and remote file systems from one system to another over the internet. It runs on the top of TCP. It uses two TCP connections i.e. data and control connections in parallel. Control Connection at port 21 and Data connection at port 20. FTP is out-of-band. Out-of-band means data that is transferred through a stream independent from the main in-band data stream.

S6. Ans(d)
Sol. BCD (Binary coded Decimal) Number is from 0 to 9, which requires four bits to store. As the maximum number of the system (15) can best represented by 4 bits. It is also called as 8421 code to represent maximum number 15.

S7. Ans.(c)

S8. Ans.(a)
Sol. Given:
R = 5 Ω
L = 0.4 H
V_dc = 50 V
Energy stored in a field is
E = 1/2 LI^2
Current in the coil is
⇒ I = V_dc/R
⇒ I = 50/5
⇒ I = 10 A
Now,
E = 1/2(0.4)〖(10)〗^2
So, E = 20 Joules

S9. Ans.(b)

S10. Ans.(c)
Sol. Packet switching is a method of transmitting data in which long messages are sub-divided into packets. In this resources are not reserved but are allocated on demand. It follows first-come first serve principle for data.

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