Quiz Electronics Engineering 19 Sep 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 19/09/2020

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

Q1. An Ethernet hub
(a) connects to a digital PBX
(b) Functions as a repeater
(c) connects to a token-ring network
(d) functions as a gateway

Q2. Norton’s Theorem is
(a) The same as Thevenin’s theorem
(b) Same as Newton’s theorem
(c) Converse of Thevenin’s theorem
(d) Cannot say

Q3. In an n-type semiconductor, as the donor concentration increases, the Fermi levelE_F:
(a) Moves towards the conduction band
(b) Remains unaltered
(c) Move towards the centre of forbidden energy gap
(d) May or may not move depending on temperature

Q4. In an unclocked R-S flip flop made of NOR gates, the forbidden input condition is:
(a) R = 0, S = 0
(b) R = 1, S = 0
(c) R = 0, S = 1
(d) R = 1, S =1

Q5. The each with a 1mm separation in air is
(a) 9 × 10^(-9) N
(b) 9 × 10^(-6) N
(c) 9 × 10^(-3) N
(d) 9 × 10^(-12) N

Q6. What is the purpose of the CRC in network communications?
(a) Request retransmission of lost packets
(b) Detect data errors
(c) Detect lost data packets
(d) Reassemble packets into their original order

Q7. Which of the following is not true about EPROM?
(a) Random Access Memory
(b) Erasable Programmable Read Only Memory
(c) Non-volatile Memory
(d) Sequential Access Memory

Q8. An upward counter can count in …. direction
(a) forward
(b) backward
(c) both (a) and (b)
(d) either (a) or (b)

Q9. If the radiated power of AM transmitter is 10 kW, the power in the carrier for modulation index of 0.6 is nearly:
(a) 8.24 KW
(b) 9.26 KW
(c) 9.6 KW
(d) 8.47 KW

Q10. Power factor of the magnetizing component of a transformer is
(a) Unity
(b) 1
(c) Zero
(d) Greater than 1

SOLUTIONS

S1. Ans.(b)
Sol. An Ethernet Hub functions as a repeater. In Telecommunication, a repeater is an electronic device which retransmits the received signal at a higher power. It is used for increasing signal strength.

S2. Ans.(c)
Sol. In Norton’s equivalent Circuit, Norton resistance is connected in parallel with the Norton Current source but in Thevenin’s equivalent circuit, Thevenin resistance is connected in series with the Thevenin Voltage source. Hence, Norton’s theorem is converse of Thevenin’s theorem.

S3. Ans.(a)

S4. Ans.(d)
Sol. The unclocked R-S flip flop made of NOR gates is equivalent to the RS latch circuit. So, The forbidden input condition in RS latch circuit is R = 1, S = 1.

S5. Ans.(c)
Sol. Given:
Q_1 = Q_2 = 1 nC = 10^(-9) C
r = 1mm = 10^(-3) m
We know that,
K = 9 × 10^9 Nm^2/C^2
According to Coulomb’s Law –
F = (KQ_1 Q_2)/r^2
Now,
F = (9 × 10^9 × 10^(-9) × 10^(-9) )/〖(10^(-3))〗^2
⇒ F = (9 × 10^(-9) )/10^(-6)
So, F = 9 × 10^(-3) N

S6. Ans.(b)
Sol. The Cyclic Redundancy Check (CRC) ) is an error-detecting code commonly used in digital networks and storage devices to detect corrupted data. The sending device calculates the CRC and adds it to the frame. The receiving device calculates the CRC when the frame is received. If the CRCs do not match, the frame has been corrupted or altered. Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents. The most common method of correcting errors is to request retransmission of the original frame.

S7. Ans.(a)
Sol. EPROM is a Non-volatile Read Only Memory and not Random Access Memory.

S8. Ans. (c)
Sol. An upward counter can count both in forward and backward direction.

S9. Ans.(d)
Sol. Given:
Radiated power (Pt) = 10kW
Modulation index (µ) = 0.6
We know that,
Pt = Pc [1+ µ^2/2]
Now, 10 = Pc [1+ 〖0.6〗^2/2]
⇒ 10 = Pc [1+0.18]
So, Pc = 10/1.18 = 8.47 KW
Therefore, The power in the carrier for modulation index of 0.6 is nearly 8.47 KW.

S10. Ans.(a)

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