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, L-2/T-l/EE[;' Date: 31/12/2012
BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA
L-2/T-1 B. Sc. Engineering Examinations 2011-2012

Sub: HUM 135 (English)

Full Marks : 210 Time : 3 Hours
ThefigU~es in the margin indicate full marks.
/ '

USo/SEP ARA TE SCRIPTS FOR EACH SECTION

••••••
__ n •••••• •••••••
_.~ •••••••••••
_ •••••••••
, ••_ ••••••••••••••••••••
,,' ••••••••••••••••••••
_ •••M ••••• ••••••••••••••• __ ••••••• • ••••••••••••••••••••••••••••••••••••••••••••• _.................. • •••••••••••••••••• _ •••••••••••••••••• __ •••••••••••••••••••••••••• "._........................ • •••••••••••• _-_ ••••••••••••••••••••••••• __ ••••••••• __ ••••••••••

SECTION-A
There are FOUR questions in this section. Answer any THREEqu.::stions , ~d
includingQ. No~as compulsory. WlCrft. b'(JffA' Y.
1.-, I"

1. (a) Explain with reference to the context any two of the following: (15)
(~~p~le. were attracted to him as bees are attr~cted to cO,smosor dahlia stalks.
(n) ~l1osophy, at all events now, was a busmess for the experts.
(iii) I was hated by large numbers of people __ the only time in my life that I
have been important enough for this to happen to me.
(b) Attempt any one of the following: (15)
(i) Do you think that' "Shooting an Elephant" is a story of imperialism? substantiate
your answer.
(ii) Commerit on the "irony and humour" in "An Astrologer's Day".
(c) Answer any three of the following questions: (15)
(i) How did Ralph organize the children on the deserted mountain? Point out some
,
leadership qualities in him~, ' ,
(ii) Why didn't the ~ive any name for the, astrologer?
(iii) Why do you think that the writer of "Shooting an Elephant" narrated the story in
both past and present tenses?
(iv) What message do you get from your study of "The Use of Philosophy"?
(v) What does the 'beastie' symbolize in "Fire on the Mountain"?

2. (a) Recast and correct any ten of the following sentences: (15)
(i) He has good knowledges ofhistory~ ~
(ii) His illusion to my failure was clear.
(iii) We hanged the picture on the wall.
(iv) Nipa was an alumnus of BUET.
(v) That medicine makes miracles.
(vi) They made less mistakes with the new calculating machine.
(vii) I am going to cut my hair.
(viii) John tore up his coat on a nail.
(ix) I have not seen him today morning.
(x) This is the kind of a day that makes me lazy.
(xi) The data (facts) is incorrect.
(xii) Hasan is seldom ever on time for his dinners.
Contd P/2
 =2=

HUM 135
Contd ... Q. NO.2

(b) Give meanings of and then make sentences with any ten of the following words: (15)
Accumulate, Abate, Condone, Discern, Elusive, Furtive, Homage,
Identical, Meddle, Ordeal, Palatable, Prevalent.

3. Amplify any one of the following ideas: (30)

(a) Only the actions of the just smell sweet, and blossom in their dust.
(b) He that is humble, ever shall Have God to be his guide.

4. Write a pr.~cis of the following passage with a suitable title: (30)

\;,?
•
Education is the process by which our mind develops through formal learning at an
institution like school, college or university. It is mental and intellectual training, which
provides opportunities of growth and helps to overcome impediments and obstacles to
progress. Again, the purpose of education is to enlighten .the individual and to develop
his/her capacity to the limit. It is also the business of education to train individuals to
make the right choices to go ahe.ad. It ennobles our mind and refines our sensibility. It
also broadens our outlook and helps us become aware of our rights and responsibilities.
According to Newman, education gives a man a clear conscious view of his own opinions
and judgements, atruth in developing them, an eloquence in expressing them and a force
in using them .. Therefore, it is often compared to light, which removes the darkness of
ignorance and helps us distinguish between right and wrong. Julius Nyerere, President of
Tanzania, in 1974 said at an international conference that the primary purpose of
education is the liberation of man from the restrictions of habits and attitudes, which limit
his humanity. He further said, education should promote humanity and universal brotherhood,
and that it could be used as a catalyst for a change for the better. How right he was!

SECTION -B
There are FOUR questions in this section. Answer any THREE questions
. including Q. No.5 as compulsory.

.5; Read the passage carefully and answer the questions that follow: . (45)

Since when have I started calling this' semi-summer the season of watermelon, I do not
know. It has been occurring to me in the last few years, when out of nowhere, suddenly
~home get filled with watermeloJ>at one of the busiest footpath markets, in
Farmgate. The juicy red pyramids that are put to raise the potential customers within one
rarely fail.
Recently, I started getting a similar kind of aura at my campus corridors, as a group of
students of our university were found determined enough to wear red and green
throughout the whole month of March. I found it quite interesting and thought of having a
talk with them.
Contd P/3
 ~'l1.~", .••• ,.•. _ ••.•

•
,"

=3=
HUM 135
Contd ••. Q. No.5

One fine morning, I found my cubicle filled up with super-fine laughter of the
watermeloned girls. They, however, came up with a humble request to join them by being
a watermelonJ7y~f on any of the weekdays that Iwould prefer; eventually I would end
up at the t.,;L..fS't~;t evening.
rv~
But my first response or rather a query to them was "why"? They seemed a little hurt My
"why?" brought a "just-fell-from-the-sky" expression on their faces, all of them started
talking almost at the same time and my tiny ~9 started filling up with words like---
. C).1h•.'cb.-
freedom, independence, green Bengal, red sun/blood, martyrs --- and 26th March. That
evening, I also noticed that the tailors' are also boiling with 'nationalistic enthusiasm', but
they denied taking any order as they were too busy with sewing the red and greens _
shelwar-kameej-du~atta-PUnjabift. I hope the spirit of Independence will not be trapped
. within the colours only, let).s'surpass the season of watermelon, let us live the spirit
everyday as we grow. I do not know if such enthusiasms are sticky enough to hold on the
attires or not It is cosier to enjoy the evening in a blind lane of Farmgate with a bowl of
watermelon after a hot":long-semi-summer-walk and a fictive-nationalism-talk with my
students ... "'um lovin' it'. Let the watermelon be seasonal only, not nationalism. Amen.
Questions:

(a) What is the passage about? What is it that the author wants to convey?
(b) Why do you think the author finds his/her students attire interesting? Do they have
anything to do with the "nationalistic enthusiasm"?

(c) "The tailors' are also boiling with 'nationalistic enthusiasm'" - comment on the
tone of the author. Was it a tone of disbelief; or of frustration; or of ridiculation?
(d) Why do you think the author is calling the "semi-summer" comprising March as
"Th~ season of watermelon"?

(e) The last word of the passage is "Amen", which suggests that it is a kind of prayer;
what is the prayer about?

6. (a) What az:ethe elements of a Report and how are they organized? Discuss briefly. (10)
(b) As the Purchase Officer of OTOBI, you had ordered 15. dozen bed sheets after
examining the samples sent by the wholesaler. When this consignment arrives you find
neither in texture nor in shades do the sheets conform to the samples you had approved.
Write a claim letter demanding their replacement
(10)
(c) Give phonetic spellings of the following words (Any Five):
(10)
yesterday, about, chair, boat, celebration, achievement

Contd P/4
 r '
!

=4=

HUM 135

7. (a) What are the styles of presentation you can follow while writing business

correspondence? (5)

(b) Write a composition on anyone of the following topics: (15)

(i) Facebook and Virtual Friendship

(ii) My Fav~)UfiteFilm
(iii) The.~~World
, f\
(c) Write a dialogue between an employer and an employee. The employer wishes to

fire/sack the employee who has been very irregular since hlst few months. (10)

8. (a) Transforrnthe following sentences as directed (Any Five): (10)

(i) Resist the devil and he will flee from you. (Simple)
(ii) I know where he was born. (Simple) .~{'
'(iii) He had all the qualifications for the post~honesty. (Compound)
(iv) One word more and I will tum you out. (Complex)
(v) As soon as he gives a command, it is carried out. (Compound)
(vi) He was sincere, and so he gained prominence. (Simple)
(b) "The main purpose of a sales letter is to convert the reader into a customer" - How is

this purpose achieved? (5)-

(c) Write short notes on any three of the following: (15)
(i) The six steps of collection procedure.
(ii) Difference between a tender and a quotation
(iii) Semantic gap
(iv) Consonants
/
. .....•.
. .

L-2/T-1/EEE Date: 31/12/2012

BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA
L-2/T-l B. Sc. Engineering Examinations 2011-2012

Sub: HUM 135 (English)

Full Marks: 210 Time: 3 Hours
The figures in the margin indicate full marks.
USE SEPARATE SCRIPTS FOR EACH SECTION

SECTION -A
There are FOUR questiop.,gin this section. Answer any THREE questions
including Q. NO.1 as compulsory .

. 1. (a) Explain with reference to the context any two of the following: (15)
(i) People were attracted to him as bees are attracted to cosmos or dahlia stalks.
(ii) philosophy, at all events now, was a business for the experts.
(iii) I was hated by large numbers of people __ the only time in my life that I
have been importl:J.l1tenough for this to happen to me.
(b) Attempt any ~ of the following: (15)
(i) Do you think that "Shooting an Elephant" is a story of imperialism? substantiate

your answer.
(ii) Comment on the "irony and humour" in "An Astrologer's Day".
(c) Answer any thr~e of the following questions: (15)
(i) How did Ralph organize the children on the deserted mountain? Point out some
leadership qualities in him.
(ii) Whydidn't the writer give any name forthe astrologer?
(iii) Why do you think that the writer of "Shooting an Elephant" narrated the story in .
both past and present tenses?
(iv) What ~essage do you get from your study of "The Use of Philosophy"?
(v) What does the 'beastie' symbolize in "Fire on the Mountain"?

2. (a) Recast and correct any ten of the following sentences: (15)
(i) He has good knowledges of history.
(i0 His illusion to my failure was clear.
(iii) We hanged the picture on the wall.
(iv) Nipa was an alumnus of BUET.
(v) That medicine makes miracles.
(vi) They made less mistakes with the new calculating machine.
(vii) I am going to cut my hair.
(viii) John tore up his coat on a nail.
(ix) I have not seen him today.morning.
(x) This is the kind ofa day that makes me lazy.
(xi) The data (facts) is incorrect.
(xii) Hasan is seldom ever on time for his. dinners.
Contd P/2
 =2=

HUM 135
Contd .•. Q. No.2
(15)
(b) Give meanings of and then make sentences with any ten of the following words:
Accumulate, Abate, Condone, Discern, Elusive, Furtive, Homage,
Identical, Meddle, Ordeal, Palatable, Prevalent.

(30)
3. Amplify any ~ of the following ideas:
(a) Only the actions of the just smell sweet, and blossom in their dust.
(b) He that is humble, ever shall Have God to be his guide.

(30)
4. Write a precis of the following passage with a suitable title:

Education is the process by. which our mind develops through formal learning at an
institution like school, college or university. It is mental and intellectual training, which
provides opportunities of growth and helps to overcome impediments and obstacles to
progress. Again, the purpose of education is to enlighten the individual and to develop
his/her capacity to the limit. It is also the business of education to train individuals to
make the right choices togo ahead. It ennobles our mind and refines our sensibility. It
also broadens our outlook and helps us become aware of our rights and responsibilities.
According to Newman, education gives a man a clear conscious view of his own opinions
and judgements, a truth in developing them, an eloquence in expressing them and a force
in using them. ~herefore, it is often compared to light, which removes the darkness of
ignorance and helps us distinguish between right and wron~. Julius Nyerere,Presidentof
Tanzania, in 1974 said at an international conference that the primary purpose of
education is the liberation of man from the restrictions of habits and attitudes, which limit
!

his humanity. He further said, education should promote humanity and universal brotherhood,
and that it could be used as a catalyst for a change for the better. How right he was!

SECTION-B
There are FOUR questions in this section. Answer any THREE questions
including Q. No.5 as compulsory.

(45)
5. Read the passage carefully and answer the questions that follow:

Since when have I started calling this semi-summer the season of watermelon, I do not
know. It haS 'been occur~ing to me in the last few years, when out of nowhere, suddenly
my walks home get filled with watermelons at one of the busiest footpath markets, in
Farmgate. The juicy red pyramids that are put to raise the potential customers within one

rarely fail.
Recently, 1 started getting a similar kind of aura at my campus conidors, as a group of
students of our university were found determined enough to wear red and green
throughout the whole month of March. I found it quite interesting and thought of11aving a

talk with them.

Contd P/3
 •

,
/
•
=3'=

HUM 135
Contd .•. Q. No.5

One fine morning, 1 found my cubicle filled up with super-fine laughter of the
watermeloned girls. They, however, came up with a humble requestto join them by being
a watermelon myself on any of the weekdays that I would prefer; eventually I would end

up at the tailors' that evening.

But my first response or rather a query to them was "why"? They seemed a little hurt. My
"why?" brought a "just-fell-from-the-sky" expression on their faces, all of them started
talking almost at the same time and my tiny cubicle started filling up with words like ---
freedom, independence, green Bengal, red sunJblood, martyrs--- and 26th March. That
evening, I also noticed that the tailors' are also boiling with 'nationalistic enthusiasm', but
they denied taking any order as they were too busy with sewing. the red and greens ---
shelwar~kameej-dupatta-punjabies. I hope the spirit of Independence will not be trapped
within the colours only, let it surpass the season of watermelon, let us live the spirit
everyday as we grow. I do not know if such enthusiasms are sticky enough to hold on the
. attires or not. It is cosier to enjoy the evening in a blind lane of Farmgate with a bowl of
watermelon after a hot-Iong-semi-summer-walk and a fictive-nationalism-talk with my
students .. .'''um lovin' it". Let the watermelon be seasonal only, not nationalism. Amen.

Questions:
(a) What is the passage about? Whatis it that the author wants to convey?
(b) Why do you think the author finds his/her students attire interesting? Do they have

anything to do with the "nationalistic enthusiasm"?

(c) "The tailors'are also boiling with 'nationalistic enthusiasm'" - comment on the
tone of the author. Was it a tone of disbelief; or of frustration; or ofridiculation?
.cd) Why do you think the author is calling the "semi-summer"comprising March as

"The season of watermelon"?

(e)The last word of the passage is "Amen", which suggests that it is a kind of prayer;

what is the prayer about?

6. (a) What are the elements ofa Report and how are they organized? Discuss briefly. (10)
(b) As the Purchase Officer of OTOBI, you had ordered 15 dozen bed sheets after
examining the samples sent by the wholesaler. When this consignment arrives you find
neither in texture nor in shades do the sheets conform to the samples you had approved.

Write a claim letter demanding their replacement. (10)

(c) Give phonetic spellings of the following words (Any Five): (10)
yesterday, about, chair, boat, celebration, achievement

eontd P/4
 ~ '.\
•

=4=

HUM 135

7. (a) What are the styles of presentation you can follow while writing business

correspondence? (5)
(b) Write a composition on' anyone of the following topics: (15)
(i) Facebook and Virtual Friendship
(ii) My Favourite Film
(iii) The Third W orId
(c) Write a dialogue between an employer and an employee. The employer wishes to

fire/sack the employee who has been very irregular since last few months. (10).

8. (a) Transform the following sentences as directed (Any Five): (10)

(i) Resist the devil and he will flee from you. (Simple)
(ii) Iknow where he was born. (Simple)
(iii)He had all the qualifications for the post except honesty. (Compound)
(iv) One word more and I will tum you out. (Complex)
(v) As soon as he gives a command, it is carried out. (Compound)
•
(vi) He was sincere, and so he gained prominence. (Simple)
(b) "The main purpose of a. sales letter is to convert the reader into a customer" - How is

this purpose achieved? (5)

(c) Write short notes on any three of the following: (15)
(i) The six steps of collection procedure.
(ii) Difference between a tender and a quotation
(iii) Semantic gap
(iv) Consonants

-------------------------------------------
..

L-2/T-1IEEE Date: 07/0112013

BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA
L-2/T -1 B. Sc. Engineering Examinations 2011-2012

Sub: HUM 277 (Fundamentals of Economics)

Full Marks: 210 Time: 3 Hours
The figures in the margin indicate full marks.
USESEPARA TE SCRIPTS FOR EACH SECTION
____ .~ __ H • __ • __ •• _, •••••••••• h ••••• •• _ ••• _ •••••••••••••••••••• , •• - •••• -_.................... • ••••••••••••••••••••••••••••••••••••• -_ •••••••••••••••••••••••••••••••••••••••• , ••••••••••••••••••••••• __ ••••••••••• _ •• , ••••••••••••••••••• " ••••••

SECTION-A
There are FOUR questions in this section. Answer any THREE.

1. (a) Illustrate the concept of production function. (5).

(b) Narrate the various forms of productivity. (10)
(c) State and prove the application of Euler's theorem in the theory of distribution of

. production. (10)
(d) Briefly discuss the various internal and external economics of scale of production. (10)

2. (a) Define optimization. How can it be achieved? Why is optimization necessary with
reference to the production of a firm? (10)
(b) Explain graphically the two conditions of equilibrium of a firm under perfectly

competitive market. (10)

(c) What is meant by the shut-down point of production of a firm? Explain graphically
the shut-down point of production of a firm under perfect competition. (5)
(d) Given the following total revenue (TR) and total cost (TC) functions for a firm (10)
(i) Set up the profit function,
(ii) Find the critical point(s) and
(iii) Calculate the maximum profit.
TR = 1000Q - 2Q2'
TC = Q3 _ 59Q2 + 1315Q + 2000

3. (a) Illustrate the concepts of national income, GNP, GDP and NNP. (5)
(b) Describethe circular flow of income and expenditure in a two sector economy. (5) .
(c) Briefly discuss the various policies for controlling inflation with reference to the
context of Bangladesh. (15)
(d) Given that (10)
GNP = Tk. 1,03,000 crore
Depreciation = Tk. 9,000 crore
Indirect tax =Tk. 12,500 crore
Subsidy is 20% of indirect tax
Calculate national income.
Contd P/2
 =2=

HUM 277

4. , (a) Explain the concept of,"vicious circle of poverty"? How can this circle be broken? (15)
(b) What are the differences 'between economic growth and economic development?
Explain the characteristics of least developed countries. (10)
(c) Explain the "Harrod-Domar" growth model of economic development. (10)

SECTION-B
There are FOUR questions in this section. Answer any THREE.

5. (a) Define demand function. (5)

(b) What are the factors thatinfluence the shifting of a demand curve? (10)
(c) What are the exceptions to the law of demand? Explain them., (10)
, (d) What is market demand? Derive the market demand for acommodity. (10)

6. (a) What are the properties of an indifference curve? Explain them. , (15)
(b) Explain consumer's equilibrium with the help of budget line and indifference curve. (10)
(c) Show that total effect of a price change is equal to substitution effect and income
effect. Present and explain all necessary diagrams. (10)

7. (a) Show that price elasticity of demand varies from zero to infinity along any straight
line demand curve. (15)
(b) What are the det~rminants of price elasticity of demand? (10)
(c) From the following table calculate elasticity of demand if you move from point A to C
and explain what you understand from the result. (10)
Point Px Qy

A 200 400
B 250 600
C 300 800

8. (a) How is price of a commodity is determined under competition? Explain graphically. (10)
(b) What will happen to the equilibrium price and quantity due to change in demand? (10)
(c) From the following demand and supply functions, calculate equilibrium price and
quantity and show the result in a graph. (15)
P=0.lQ+8
P =-0.5Q + 50
(i) If a per unit tax. of Tk. 2 is imposed, how will it effect the equilibrium price and
quantity?
(ii) What will happen to the equilibrium price and quantity if government provides a
subsidy of Tk. 3 per unit?

-----------------------------.-----------
X'~""'.'.'"
,r

"
.,_

.-:

L-2/T-1/EEE Date: 19/11/2012

BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA
L-2/T-1 B. Sc. Engineering Examinations 2011-2012
Sub: EEE 203 (Energy Conversion I)
Full Marks: 210 Time: 3 Hours
USE SEPARATE SCRIPTS FOR EACH SECTION
, The figures in the margin indicate full marks.

SECTION -A
There are FOUR questions in this Section. Answer any THREE.

1. (a) What are the analogues parameters in the,magnetic circuit corresponding to V, I, R

and G in the electric circuit? A flux of 4.8 mwb is produced when a current of 0.34 Amp
is applied to a coil. Find the number of turns of the coil if the area of cross section of the
core is 0.01 m.sq. and the average length of the flux path of the core is 0.45 m and

Ilr = 2500 and IlO = 4n (10-7). (17 ~)

(b) A ferromagnetic core with a relative permeability of 2000 is shown in the figure
along with other dimensions. The depth of the core is 7' em. Because of fringing effects
the effective area of the air gaps is 5% larger than their physical size. What is the flux in
each of the left, centre and rightlegs of the core if the current in the coil is 1.0 Amp.? (17 ~)
30cm JOcm

'f -0.05 em
300 turns
0.07 cm-

r
IOcill
,1- c" .• ,:.,~' •• ~.; .• ....: •• .-'"

",.,/i;'fJ' ,,,{cY , Q..J(~

2. (a) What are the tests required to determine the parameters of the equivalent circuit of a
transformer? Why the core loss is neglected in the short circuit test? What are the
parameters obtained from this test? Write the expressions to determine these parameters.
How much voltage is applied during this test? Will the parameters obtained from this
test be referred to H.T or.L.T side? (17 ~)
(b) A 10 KVA, 2300/230 V, single phase transformer has the following resistance and

. reactance:
(17 ~)

Rp = 4.4 n, Rs = 0.04 n, Rc = 48 Kn, XM = 4.5 Kn, Xp = 5.5 n, Xs = 0.60 n

The impedances of the excitation branch are given referred to H.T side of the
transformer. Find
(i) The equivalent circuit referred to H.T side
(ii) The equivalent circuit referred to L.T side
(iii) The per unit equivalent circuit.
Contd P12
 .,
'= 2=
EEE 203

3. (a) What are the factors on which the voltage regulation of a transfomier depends?
Drawing appropriate vector diagrams show that the voltage regulation is higher in case

of lagging load compared to that of leading load. (17 X)

(b) A 10 KVA, 2300/230 volt transformer is supplying rated load at rated voltage and at
a power factor of 0.8 lagging. Its equivalent resistance and reactance, referred to H.T
side, are Req = 8.4 Q and Xeq = j 11.5 Q. During the open circuit test, the wattmeter

reading was 115 watt. Find; (17 X)

(i) Input voltage
1-(;.1~..;.

(ii)Voltage regulation and

(iii) Efficiency.

4. ,(a) ~~lf.~fi~~~ay efficiency? Why is it important in case of distribution transformers?

Show th~('the maximum efficiency of a transformer can be achieved if t~e variable

losses are equal to the fixed losses. (17 X)

(b) A single phase, 12 KVA, 480/120 volt transformer is operating under maximum
efficiency condition. The load is connected to L.T side of the transformer consuming 10

Amp. If the core loss is 38 watt, what is the equivalent resistance referred to L.T side? (17 X)

SECTION-B
There are FOUR questions in this section. Answer any THREE.

5. (a) With neat sketches, explain how the rotating magnetic field is developed in the stator
of a 3-phase, 2-pole induction motor. Also mathematically derive the expression of

magr:teticfield and show that it is a rotating field. (10)

(b) A three phase 230-V, 60-Hz, A50-hp, six pole induction motor operating at rated
conditions has 91% efficiency and draws a line current of 124 A. The core loss, stator
copper loss and rotor conductor loss are 848 W, 1400 Wand 775 W, respectively. Draw
the power flow diagram of the motor,_and show numerical values of all the different
losses, input power, air gap power and mechanically developed power in the diagram.
Show detailed calculations. (15)
(c) A three phase four pole motor is drawing 200 A line current at 208 V (line to line) at
0.8 pf (lagging). If the efficiency of the motor is 96%, calculate the shaft torque of the
motor. (10)

Contd Pl3
 c
=3 =,

EEE 203

6. (a) The following test data were obtained from no-load, blocked-rotor, and DC test ofa
three~phase, wye-connected 40-hp, 60-Hz,460-V, design B induction motor whose
rated current is57.8 A. Blocked rotor test was made at 15 Hz. (20)
Blocked Rotor No Load DC
Vline= 36.2 V Vline= 460.0 V VDc = 12.0 V

lline= 58.0 A lline= 30 A Inc = 59.0 A

P3phase= 2570 W P3phase= 4660 W

(For Design B, Xl = 0.4 XBR, X2 = 0.6 XBR)

(i) Draw the equivalent circuit of the motor referred to stator, showing numerical
values of each circuit parameter. Show detailed calculation for determining
the numerical values;
(ii) Find the combined Core and Friction and Windage loss.
(b) The rotor of a 25 hp six pole 50 Hz induction motor has equivalent resistance and
equivalent reactance per phase of 0.1 n and 0.54 n, respectively. lfthe slip of the motor
is 0.02, then determine (i) rotor speed in rpm (ii) rotor impedance (iii) rotor current. (15)

7. (a) A three phase 25 hp, 230 V, 60 Hz two pIe induction motor drives a load that
demands a constant torque regardless of the speed. (The load torque is independent of
speed) The machine. is 'operating at rated voltage, rated frequency and rated speed of
3575 rpm. Determine shaft horse power, speed and efficiency if the frequency drops to
54 Hz. The power factor and line current for the new condition are 89 percent and 55 A,
respectively, and the respective stator conductor loss, rotor conductor loss and core loss
are 992.7 W, 496 Wand 546 W. (20)
(b) Consider the 4 pole motor whose name, plate is given in Figure for Question 7(b) (i). (15)
Find the minimum locked rotor torque, minimum breakdown torque starting torque and
maximum expected starting current for the motor.

3 PHASE INDUCTION MOTOR

ULTRA POWER SERIES

MODEL NO. TB0014DFA

VOLTS 208-230/460 AMP. 3.8-3.6/1.8
.. ENCL. OOP FRAME NO. 143T
MAXAMB 40°C SERVICE FACTOR 1.15
HP 1 TIME RATING CaNT. BRG.. I D.E. 620SZZ
RPM 1720 KVACODEC NO. I O.D.E. 620SZZ
INS. B NEMA F. L. EFF. 77 NEMA DESIGN B
HZ 60 DATE CODE 0396 SER # 001687411

Figure for Question 7(b) (i)

Contd P/4
 .•

=4=

EEE 203
Contd Q. No. 7(b)
,

Design Design Design Design

Data for 1hp Motor
A&B C D E

Minimum Locked Rotor

275% 285% 275% 190%
Torquein percent of Full
Load Torque
Minimum Breakdown
300% 200% -- --
Torque in percent of full
load torque
Figure for Question 7(b) (ii).

NEMA code letters for locked-rotor kVA per horsepower

Code
COde kVA/hpb
Letter. kVA/hpb Letter

K 8.0-9.0
A 0.0-:'3.15
L 9.0-10.0
B 3.15-3.55
C 3.55-4.0 \1 10.0-11.2
N 11.2-12.5
o 4.0-4.5
P 12.5-14.0
E 4.5-5.0
R 14.0-16.0
F 5.0-5.6
S 16.0-18.0
G 5.6-6.3
T 18.0-20.0
H 6.3-7.1
7.1-8.0 U 20.0-22.4
J 22.4 and up
V

Figure for Question 7(b) (iii).

8. (a) The main and auxiliary windings of a hypothetical 120-V, 60 Hz, split-phase motor
have the rollowing locked rotor parameters: Rmw= 2.00 n, Xmw= 3.50 n, Raw= 9.15 n,
X = 8.40 n. The motor is cOlUlected to a 120 V 60 Hz system. It is given that
aw
k = 1.0, Ib-ftlA2• Determine (i) the locked rotor torque in lb- (ii) Capacitance required
sp
in series with the auxiliary winding in order to obtain a 90 phase displacement between.
the current in main winding and current in auxiliary winding. (iii) locked rotor torque

after connecting the capacitor with capacitance value of (ii). (20)

(b) Draw equivalent circuit diagram and torque speed characteristics of (i) Capacitor
Start Motor, (ii) Permanent Split Capacitor, (iii) Capacitor Start Capacitor Run single
phase induction motor. Briefly describe the operation of a shaded pole motor with

diagram. (15)

-----------------------------------

,
i
.~ r5)(]./
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L-2/T-l/EEE Date: 17/12/2012
BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA
L-2/T-l B. Sc. Engineering Examinations 2011-2012

Sub: EEE 201 (Electronics I)

FuU Marks: 210 Time: 3 Hours
The figures in the margin indicate. fuU marks.
USE SEPARATE SCRIPTS FOR EACH SECTION

SECTION-A
There are FOUR questions in this section. Answer any THREE.

1. (a) Show that the diode small-signal incremental resistance is given by, rd = __
fJVT .
In
Where the symbols have their usual meanings.
(17)
(b}IfRs = 260 n, find volvs for 1= 1 rnA and I = 0.01 rnA for the circuit shown in Fig. Q. 1(b).
(18)
or," ••• _ •• ~ ".........
.+V
••••••• ""' •• "_.~ ••••••
>

..~.., ~s- ..__ '.'.......-\;... ~ - ..

. . . oC 'f D~Jc
-f'"
"""-'~".'._ _ _~
..- _ .. .. ..

""
.•.....O."'"_''';-)V~''' J.-.L

......
=......: ....
.• .. .. . .

,.1j'tr~~1\o),
2. (a) Consider the Zener diode circuit shown in Fig. Q. 2(a). (i) Determine V with no load
o
(ii) Find the change in the output voltave if VPS changes by :t I V (iii) Find V0 if VPS = 10 V
and RL = 2 kn. Given: Vz = 5.6V at z.= OJ mA and rz = 10 n.
(20)

V1)

RL ~rl .
{;"a-..ix 2. (~),
(b) Find the value of R and the junction area of each diode (assume aU four diodes are
identical) relative to a diode with 0.7 V drop at 1 rnA current. Given: n
-
= 1 and V = 3 V
.
o
when IL == 0 and Vo changes by 40 mV per 1 mA of load current. (15)

Contd P/2
 ",

=2=
EEE201

3. (a) A full-wave rectifier is to be designed to produce a peak output voltage of 12 V,

deliver 120 rnA to the load, and produce an output with a ripple (Vr) of not more than 5

percent. An input line voltage of 120 V (rms), 50 Hz is available. (20)

(b) Find the steady-state output of the circuit shown in Fig. Q. 3(b) . (15)

.' _ Vc -
_ _-' .. -.....
~4 . .- . ...\'. ......•.•....•...•...•......•.

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..-'\/~!i;.fCt-~
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-+
-
'.
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- ...
- ...\V
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- ....
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~':.\j'-'"
.•..••....•......••....•.....• _.•_.~.~- ._ •.. c , :.•. _._.~ .. _ _._ __ ._..••. ~ .• _.~._ _, ~ .

4. (a) For the de circuit in Fig. Q. 4(a), assume the MOSFET parameters are Vtn = 2 V,
2
K~ = 80 JlAN , and WIL = 4. Choose R1 and R2 such that the current in the bias

resistors is approximately one-tenth of!D. Assume 1D= 0.5 rnA. (20)

."-~ri5~:tl:
..-_ -

...,....,...-t-_. .._ _-- -"_ _ ..__ : :._ ,..__ _ _._._._-~_ _ _.-

-~- ------~- -2::15,~--_-til,R!t[Ii'J

-5"
••••
--:'~ ••••*_.ft ••••••
__ "*__ ~_........ •• ••••.••..•••••.
_ ••~~•••_ ••__ .__ ••~._ ••...••
~.•••••••••._~ ••. ............;"
••• w ._ ••••• "w" •••...•.••••
.- ••_ •••__ •

(b) Draw the VTC ofa CMOS inverter. Find the minimum permitted logic-I, VIH' (15)

SECTION-B
There are FOUR questions in this section. Answer any THREE.
The symbols have their usual meanings.'

5. (a) For the source follower circuit shown in Fig. Sea) calculate the input resistance, output'
'resistance, voltage gain, open circuit voltage gain and overall gain. Why it is called
source follower? (15+2)
, 2 2
(b) Design the amplifier circuit shown in Fig. 5(b) if K ~ 1 = 1mAIV , K ~ 2 = 400 JlA/V ,

Vtl = Vt2 = 1:2 V, 101 = 0.2 rnA, 102 =O.5mA, VOS1 = VDS2 = 6 V, Rin = 100 kQ and

Rsi = 4k.Q. Neglect the ehannellength modulation effect and assume W/L = 1. (18)

Contd P/3
 =3=

6. (a) Draw the different biasing arrangement ofa BJT amplifier circuit and state their
(19)
advantages and disadvantages.
(b) Determine the small signal voltage gain and output resistance of the common-gate
2
circuit shown in Fig ..6(b). Wnen IBias = 0.2 rnA, Vtn == IVtpl = 0.8 V, K~ = Kp= 0.4 mA/V ,

(16)
A. = A.p = 0.01 V-land W/L = 1 for all the transistors.
n

e
7. (a) For the circuit shown in Fig. 7(a), determine the small signal parametersgm, rn and r

o
for both the transistors, the overall small. signal voltage gain Av ;: V , input resistance
. Vs

Rin and output resistance Rout. Here ~ = 120. (25)

(b) For the transistor circui, shown in Fig. 7(b), p ~ 30. Determine V 1 such iliat V CE ~ 6 V. (10)

8. (a)For the circuit shown in Fig. 8(a),thetransistor parameters are Rl = 10 kQ, ~ = 50

and VBE! = VBE2 = 0.7 V. Determine IBb IB2, ICI and IC2. Assume that all the
(10)
transistors are identical.
(b) Consider the, common base circuit in Fig. 8(b), the transistor parameters are ~ =120
(16)
and V A = oc.Determine the bias point (Q point) and small signal voltage gain vo/vs.

(c) For the circuit shown in Fig. 8(c), find the value of the base voltage so that the transistor
(7)
operates insaturation with a forced ~ of 5.

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..
L-2/T-l/EEE Date: 24/12/2012
. BANGLADESH UNIVERSITY OF ENGINEERING ANp TECHNOLOGY, DHAKA
L-2/T-l B. Sc. Engineering Examinations 2011-2012
Sub : MATH 259 (Linear Algebra)
Full Marks: 210 Time: 3 Hours
The figures i~ the margin indicate full marks.
USE SEPARATE SCRIPTS FOR EACH SECTION

SECTION-A
, )
There are FOUR questions in this section. Answer any THREE.
Symbols used have their usual meanings.

1. (a) Prove that every square matrix can be expressed in one and only'one way as the sum

of a symmetric matrix and a skew symmetric matrix. (11)

(b) Solve the following 'system of linear equations: (12)

Xl + 2X2- 3X3+ X4= 4

- 2XI + X2+ 2X3+ X4= - 1
- Xl + 3X2- X3+ 2X4= 3
4XI - 7X2..;,5X4= - 5

2+x 3+x x
(c) Solve the following equation 1 + x x 3 +x = O. (12)
x l+x 2+x

1 2 -2 -1
-1 -4 4 0
2. (a) Compute the inverse of A = . Also express Aas a product of
2 -7 4 -7
1 6 -5 1

elementary matrices.
(18)

(b) Find the canonical matrix row equivalent to the following matrix: (17)

1 2 3 4
2 7 3 5
3 8 1 -2
2 4 6 8

Also find the rank of the matrix.

1 2 3 4
2 :3 4 6
3. (a) Reduce A = to the normal' form B and compute the matrices P
3 4 5 7
4 5 5 7

. and Q such that PA Q = B. (18)

Contd P/2
 =2=

MATH 259(EEE),
Contd ••• Q. No. 3(a)

19 -9
(b) Given,A = .. 25 .,..11 -6J
- 9 . Determine whether A is diagonalizable. If so, find .
[
17 -9 -4

a matrix P that diagonalizes A, and determine p-I AP. (17)

4. (a) State Cayley-Hamilton theorem. Verify Cayley-Hamilton theorem for the matrix

1 -1

A =[ ~ 2 IJ
~ and hence find A-~.
. (18)
o

(b) Reduce the following quadratic form q to the canonical form and find the rank, index
and signature 6f q. Also write down the corresponding equations of transformations.

q =4 xf +3 xi - xi + 2x2X3 - 4XJXI+ 4XIXi. (17)

SECTION-B
There are FOUR questions in this Section. Answer any THREE.

5. (a) Find the standard matrix for the transformation T on R3, where T is the composition
of a rotation of 45° about y-axis, followed bya reflection about yz-plane, followed by a

dilation with factor k = J2. Then find T(2, - 5, 8) using the standard matrix. . (18)
(b) Consider the set P2 of all polynomials of degree 2 and the set S = {Ph P2, P3} where,
PI = 1 + x, P2 = 1 + x2, P3= X + x2. Is the set S a basis for P2? If so, then find the
coordinate vector of the polynomial p(x) = 2 - x + x2 relative to the basis S. (17)

6. (a) (i) Find a subset of vectors VI =(1, - 2, 0, 3), V2 = (2, - 5, - 3, 6),

V3 = (-4, 11,9,- 12), V4 = (2, - 1,4,- 7) and Vs = (5, - 3, 11,- 11) that forms a basis for
the space spanned by these vectors. (ii) Express each vector not in the basis as a linear

combination of the basis vectors. (17) .

(b) Find the Kernel and Range' of (i) orthogonal projection on xz-plane; (ii) orthogonal
projection on the plane defined by x = z. Write down a basis and the dimension of Kernel

and Range in each case. (18)

Contd P/3
 •
/
j

,,/

;/
,/

MATH 259(EEE)
=3'=

,
7. (a) Consider the set ofa112 x 2 matrices of the form
" ,
[a
1 b
1] , where a, b are real numbers. ,
Is the above set with standard matrix addition and scalar multiplication a vector space?

If not then show all the axioms of vector space that fail to hold. (17)
4
(b) Determine whether the following subsets are subspaces ofR • If so, then find a basis

in each case and their dimensions. (18)

(i) all vectors of the form (a, b, c, d), where d = 2a + 7c and 3c = 2a - 5b.

(ii) all vectors of the form (a, b, 0, c), where Sa = 3c.

8. (a) Let T: P2 -+ P3 be the linear transformation defined by T(P(x»= x p(x - 3), that is
T(a + bx + cx2) = x(a + b(x - 3) + c(x - 3i). Find the m~trix for T with respect to the
standard bases B = {I, X, x2} and B' = {I, X, x;x3}. If X = p(x) is any element in P2, then verify

that [T]B',B[X]B= [T(X)]B/ (17)

(b) Consider the vector space R3 with the Euclidean inner product. Apply Gram-Schmidt
process to transform the basis vectors, UI = (1, 1, 1), U2 = (- 1, 1, 0), and U3 = (1, 2, 1) ,
into an orthogonal basis {v}, V2, V3}; then normalize the orthogonal basis vectors to

obtain the orthonormal basis {q}, Q2, Q3}' (18)

--------------------------------------~----