Download Annexure 2 (Differences with Answer Key on LDCE for

1
Annexure –II: Differences with Answer Key on LDCE for TTA-2015
SECTION-1
QUESTION No.
QUESTION
ANSWER
KEY
PUBLISHED
D
1
In a three-phase circuit, the total
instantaneous power is equal to
instantaneous power per phase
multiplied by
9
Ohm’s law is applicable to
D
13
Latent heat of vaporization of
Refrigerant should be
A
14
Which one of the following types
of air-conditioning plant
becomes a necessity when areas
to be air-conditioned are large ?
D
20
A zener diode
B
REASON FOR DIFFERENCE WITH ANSWER KEY
Multiple Answers: Both A and D are correct
based on the conditions applied:
P= 3VpIpCosø
Reference: Elements of Electrical Engineering.
By: M. Mariya Louis, Page-455 (Please see
attachment in Annexure-1, Q 1 )
Wrong Answer: Correct answer C:
Ohm’s Law generally applicable for
electrolytes in solution also
Reference: Modern Electro chemistry: Ionics .
Volume-1
By: John OM Bockris and Amulya KN Reddy
Page- 588;
(Please see attachment in Annexure-1, Q 9 )
Question is confusing not specific, giving two
interpretations and give two answers B and
A:
For small units the latent heat capacity of the
refrigerant is less a favourable factor than for
large compressor operation
Reference: Fundamentals of food freezing
By: Norman W Desrosier and Donald Kiteley
Resseler. (Please see attachment in
Annexure-1, Q 13 )
Wrong Answer: Correct answer C:
(Package type used for large area and Central
Air-condition System used in very large area )
Package air-conditioning can be considered as
the bigger versions of the room airconditioner and are used for air-conditioning
loads beyond the capacity range of the room
air-conditioners.
Reference: Basic refrigeration and Airconditioning, Page: 286
By: Anantha Narayanan (Please see
attachment in Annexure-1, Q 14 )
Answer in B incorrect, all answers are
incorrect:
A zener diode has sharp breakdown happens
it’s rated regulating voltage ( which may low
or high reverse ), not always in low reverse
voltage only.
Zenner Voltage Vz = Vo = Vin – RI
Reference: 1. Physics ( Volume 1 and 2 )Page-1338
By: Sathya Prakash
Reference 2. Principles of Electronics
By: V K Mehta- Page 109
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Annexure –II: Differences with Answer Key on LDCE for TTA-2015
(Please see attachment in Annexure-1, Q 20 2 pages )
23
Inverter converts
A
28
Decibel is defined in terms of
A
37
The difference between Phase
and Frequency modulation
D
40
The measure of mismatch
between the load and the
transmission line is known as
D
Printing Mistake: Both answers in B and D are
same
Multiple Answers: A, B and C are correct
based on the conditions applied:
Decibel (abbreviated as dB) is a logarithmic
expression of the ratio between two signal’s
Voltage or Current or Power levels.
Sdbv = 20 log10(V2/V1)
SdbA = 20 log10(A2/A1)
SdbP = 10 log10(P2/P1)
Reference site: whatis.techtarget.com.
(Please see attachment in Annexure-1, Q 283 pages )
Reference, Problem Example: Biomedical
Engineering e-Mega Reference: Page-84
By: Buddy D Ratner, Allan S Hoffman
Multiple Answers: B and D are correct:
The difference between Phase Modulation
and Frequency Modulation appears only in
the transmission of a Modulation Frequency
Band.
Reference: Frequency Modulation Theory:
Application to Microwave Links- Page-72
By: Jacques Fagot, philppie Magne ( Please see
attachment in Annexure-1, Q 37 )
Wrong Answer: Correct answer C:
The Standing Wave Ratio(SWR) is the
measure of mismatch between the load and
the line.
The ratio of Reflected wave to the incident
wave is known as Reflection Coefficient
Reference 1: Electronic Communication
Systems: Page – 196
By : Kennedy
Reference 2: Designing CDMA 2000 Systems:
Page – 561
By: Loenhard Korowajczuk, Bruno D Souza
Reference 3: RF Circuit design, Page-104
By: Christopher Bowick
( Please see attachment in Annexure-1, Q 40,
4 pages )
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Annexure –II: Differences with Answer Key on LDCE for TTA-2015
SECTION-II ( DEPARTMENTAL PRACTICES )
SECTION-II
QUESTION No.
QUESTION
ANSWER
KEY
PUBLISHED
3
Which one of the following
statements is false
D
7
Which one of the following is not a
function of Switch Module of 5ESS NT
switching system ?
C
9
Which one of the following is not a
subsystem of EWSD Exchange
Configuration
C
15
Which one of the following
statements is True
A
21
As per the four stroke working
principle of diesel engine, in which the
following strokes does the position
draws fresh air into the cylinder on its
downward travel?
C
23
VRLA batteries works on the principle
of
A
REASON
Out of Syllabus: Syllabus include
C-DOT RAX/SBM/MBM/E-10B/MAX-I and their working
principles only.
Out of Syllabus: Syllabus include
C-DOT RAX/SBM/MBM/E-10B/MAX-I and their working
principles only.
Out of Syllabus: Syllabus include
C-DOT RAX/SBM/MBM/E-10B/MAX-I and their working
principles only.
Out of Syllabus: Syllabus include
C-DOT RAX/SBM/MBM/E-10B/MAX-I and their working
principles only
Answering word improper:
Answer ‘Admission Stroke’ is very
unfamiliar word, instead ‘Intake
Stroke’ or ‘Suction Stroke’ are
generally used.
Reference1: Power Generation
Technologies, Page-100
By: Paul Breeze
Reference2: Modern Diesel
Technology Diesel Engines
Page- 47
By: Sean Bennet
Reference3: An Introduction to
Compact and Automotive Diesels
Page- 14
By: Edward Ralbowsky
( Please see attachment in
Annexure-1- SECTION-II, Q 21, 3
pages )
Multiple Answers: A and B are
correct:
Smaller constant current charging
also applicable for VRLA Batteries
Reference1 : Manufacture
Engineering and Environment
Engineering
Page- 925
By: P Ren Z Du
Reference2 : Valve Regulated
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Annexure –II: Differences with Answer Key on LDCE for TTA-2015
Lead Acid Batteries
Page- 157
By: Patrick T Moseley
( Please see attachment in
Annexure-1- SECTION-II, Q 23, 2
pages )
26
30
Repair work on the PCB with solder
mask is very difficult because
Which one of the following is used to
remove surplus solder from the joint
B
B
Wrong concept in Answer: All are
wrong answers.
The solder mask is thin film of
epoxy used to protect copper PCB
tracks from solder during the
component assembly process. It is
an added advantage in soldering
process for avoiding the spreading
of solder along the copper tracks.
Thus solder covered the required
Pad area only and avoid the solder
masked area.
Reference 1: Images of Solder
Mask
Reference 2: Failure Modes and
Mechanisms in Electronic
Packages
Page:28
By: P. Singh, Puligandha
Vishwanatham
( Please see attachment in
Annexure-1- SECTION-II, Q 26, 4
pages
Wrong concept in Answer: All are
wrong answers
De-soldering Wick ( De-soldering
Braid ) or de-soldering pump is
used to remove surplus solder
from joints. Repeated use of
soldering bit for removing surplus
solder will damage the
components
Reference 1: Images of desoldering Wick/ de-soldering
pump
Reference 2: Hand Book of
Electronic Package design
Page:830
By: Michel Pecht
( Please see attachment in
Annexure-1- SECTION-II, Q 30, 4
pages )
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Annexure –II: Differences with Answer Key on LDCE for TTA-2015
37
45
49
Which one of the following
statements is true as per Circle office
Restructuring in BSNL
For discrete connectors , which one of
the following is designed to cut the
insulated conductor to size and crimp
the wire connections fully assuring
electrical continuity between the two
poly ethylene insulated conductors
Which one of the following is not an
objective of earthing?
B
B
D
Out of Syllabus: Syllabus include
Organisational Setup only.
Wrong Answer or wrong
Terminology used: ALL ARE
WRONG ANSWERS:
Crimping Tools are generally used
for crimping the lugs on metal
wire of plastic/ fibre twines. Here
the proper answer to this question
is KRONE Tool or OSA Tool .
Multiple answers: Both C and D
are correct answers:
Earth is not divert the stray RF
energy from sensitive audio,
video, control and computer
equipment to anywhere. Instead it
receives it to ground to protect
the function and equipments.