L-3rr-l/EEE Date: 07/06/2014

@NC<ttter1. if 6//1

L-3rr-l/EEE _ Date: 07/06/2014BANOLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA

L-3/T-l B. Sc. Engineering Examimltions 2012-2013

Sub: EEE 301 (Continuous Signals and Linear Systems)

Full Marks: 210 Time: 3 Hours

The figures in the margin indicate full marks.USE SEPARATE SCRIPTS FOR EACH SECTION

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

Symbols bear their usual meanings.

1. (a) Consider the following.signal (12)x(t) = d o(sint) + (l - a) o(t - kn)

o < a < 1. k = :t 1, :t3, :tS, 00

Is the signal periodic? Give reason. In the case of perio.dic signal, determine the

fundamental period. Finally, sketch the signal, when a = 0.5.

(b) Determine whether the following signal is power or energy signal or neither. Justify

the apswer. (12)

x(t) = kt+4 0 (3t - k) sin2(1tt)k=-4 3

(c) Let xo(t) and xe(t) represent the odd and even parts of an" input signal x(t),

respectively: Tlle output of a system is such that

y(t)= xe(t) - xo(t)

Is the system invertible? If yes, specify the inverse .

(11)

.-2. (a) Determine whether the following systems are (18)

• linear or nonlinear • time invariant or time variant

.'causal or non causal -. memory less of with memory

• invertible or noninvertible • stable or unstable

(i) y(t)= f:-3 x(r)dt

(ii) y(t}=~l x(t)l-nt2

(b) Determine the output yet) of the system shown in Fig. for Q. No. 2(b), if the input (17)

x(t) = (_1)k 8(t--l0k), k=0,,:tl,:t2, 00

The impulse responses are given as

<ft+)

Contd p/2

~'l. C+)

h2(t) = 8 (l - 1)

h4(tJ == reet (tI2)

-{3Lt)~1 (1)

-ha.iitr (~&. No. 2(b)-'

?((+) .

=:=2=EEE 301

3. An LTl system is ciefined by the following differential ~quation

y'"(t) + 3y"(t)- y'(t)- 2y(t) = 3x"(t)- x(t}

(i) Draw the simulation diagram of the system using the canonical form-II.

(ii) Why integrators are used in the simulation diagram instead of differentiators?

(iii) Find the state equation of the system.

(iv) Determine the state transition matrix of the system using the Cayley-Hamilton

method.

(v) Describe the significance of state transition matrix in view of evaluating the'

impulse response of the system and determining the stability of the system.

(35)

"

4. (a) Three orthogonal basis functions <1>], <1>2and <1>3in an interval 0:::;t:::;3 are given below: (17)

. (t ) = {o °:::;t :::;.-Y '2-<1>3 l2--I'<t:::;3

Express x(t) shown in Fig. for Q. No. 4(a) in terms O[<I>I(t), <l>2(t) and <l>3(t).

~(t)

o-t

1 .2.. .3

hlj.:In ~ f AJ0 • 4' (a.) .

(b) Consider the circuit shown in Fig. for Q. No. 4(b). The input x(t) of the circuit is the. .

half-wave rectified signal shown in this figure. Find the amplitude of the second and

fourth harmonics of the output yet). (18)

tj(t) .

eontd P/3

.•=3=

EEE 301.SECTION-B

There are FOUR questions in this'section. AIiswer any THREE.

5. (a) Find the Fourier transforms of the following signals - (i) 8(t), (ii) 1, (iii) ejroot,

(iv) <;osroot, (v) sin root. (12)

(b) Consider the three related signals shown in Fig. 5(b). Determine X( ro) and using

Fourier transform properties, compute Y)(ro) and Y2(ro) from X(ro). (15)

. (c) Show that convolution in time domain is equivalent to multiplication in the frequency

domain. (8)

(12)

6. (a) Write down the frequency response of ideal low-pass filter with cutoff frequency roc.

Compute the impulse response of the filter and draw it. Comment on causality of the filter. (8)

(b) Consider ~he system shown in Fig. 6(b), where (15)

x(t) = sin (ro8t/2),-1rt

p(t) = t 8(t ~~J'n=-<X) ro8

h(t) = sin (3ro8t/2).nt .

Find X(ro), P(ro), Zero), H(ro), Y(ro), S(ro) and draw each of those.

(c) Consider the system shown in Fig. 6(c). The systems h)(t) and h2(t), respectively,

have fr~quency responses

H1(ro) = ~ [Ho(ro - roo)+ Ho (ro+ roo)]_ 2 .

H2(ro) = ;; [Ho(ro-roo)-Ho (ro+roo)]

Draw H) (ro), Hz(ro), Xt(ro), Xz(ro) and Y(ro).

7. (a) consider the signal x(t) givyn in Fig. 7(a). Determine the Laplace transform of Ix(t)l. (10)

(b) State the final-value theorem and prove it. (5)

(c) Find the impulse response of the system whose input and output are e-Zt u(t) and. \.

(e-t _ 3e-2t) u(t), respectively. (5)

(d) Draw (i) f-v analogous electrical circuit and (ii) f-i analogous electrical circuit for the

mechanical system shown in Fig. 7(d). If the applied velocity, u(t) = 5 m/sec along withleI .

M = - kg, D = -'--N-sec/m, K = 1 mIN, then determine the force fft) on the mass M6 - 5 . \ ,

[assume that the system Was initially ~elaxed].

Contd P/4

(15)

, .

=4=EEE30i

8. (a) (i) Find H(s) of a system described by

v'(t) = A vet) + b x(t)

yet) = c vet) + d x(t)

(ii) Evaluate H(s) for the case-

(20)

A=[-3 4]. -2 3 '

c=[-1 -1],

willi v\o)~[ ~I ld=2

Comment on stability of the system. Also find the step response of the system.

(b) For the circuit shown in Fig. 8(b), let vc(O) = 1 volt, iL(O) = 2 amperes and x(t) = u(t),

(i) draw the transformed model, (ii) find the expressions ofY(s) and yet). (15)

_ 't=::""."=:-:...J .

~(-6)I ,

-7

w

'7-(-/;) -h /:f) ~(£ . (:) 1- S (j;)== fit-l)

Pei)

-':;8" '1;o'Jz- ~. 'lUi" tib)

y ••• ., .• •

:1.

'I '2.t T+'t 2.Ti"<:' t

-1.. ...--- -

Rd' -jrx &. 110- y-(~

, It[-t)

/(

'. '2H -I~ .

I H.." t

. t F_.Jilt)

L-3ff-l/EEE Date: 17/05/2014BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA

L-3/T-1 B. Sc. Engineering Examinations 2012-2013

Sub: EEE 305 (Power System)


The figures in the margin indicate full marks.

USE SEPARATE SCRIPTS FOR EACH SECTION

..}' SECTION - A

There are FOUR questions in this section. Answer any THREE.

1. (a) Consider the following transmission matrix

T;[~~]where A, B, C, D are the generalized circuit constants of a transmission line. Find the

transmission matrix for the cascade connection shown in Fig. for Q. No. l(a) .

(5)

.j':

..+;...~~....6 .

(b) Show that an equivalent 7t model of a long transmission line can be developed by

using modified circuit parameters.

(c) A 50-Hz three:-phase transmission line is .175 mile long. It has a total series impedance

of35 + j 400 and a shunt admittance of930 x 10-6 L90° S. It delivers 40 MW at 220 kV,

with 90% p.f. lagging. Find voltage at sending by (i) short line approximation,

(ii) nominal-7t approximation, (iii) long-line equation.

2. (a) Derive the sequence circuit for a symmetrical transmission line. Comment on the

characteristics of the sequence impedances...

(b) A V-connected synchronous has sequence reactances Xo = 0.09, Xl = 0.22, X2 = 0.36(p.u.). Neutral point of machine is grounded through a reactance of 0.09 p.u. The

machine, running on no load, suffer~ a fault at its terminal. The fault currents are Ia = 0,

Ib= 3.75 LI50°, Ie = 3.75 L30° (p.u.) with respect to phase 'a' line to neutral voltage.

Determine

(i) Terminal voltages in each phase of the machine with respect to ground.'i.~'

(ii) Voltage of neutral point of the machine with respect to ground.

(iii) The type of fault.Contd P/2

(13)

(17)

(15+5)

(15)

=2=

EEE305

3. (a) Develop an equivalent network showing the interconnection of sequence networks to

simulate a double.lihe to ground fault.

(b) Discuss the simplifications made in fault analysis.

(c) Consider a small system. The bus impedance matrices are given by

(15)

(5)

(15)

(0) _ .Zbus -

jO.19,>' 0

o jO.08

o jO.08o 0

ojO.08j0.58o

ooo

jO.19

Z(1) - Z(2) -bus - bus-

j0.1437 j0.1211 jO.0789 jO.0563

j0.1211 jO.1696 j0.1104 jO.0789

jO.0789 j0.1104 j0.1696 jO.1211

jO.0563 jO.0789 jO.1211 jO.l437

: .','

Find the per unit subtransient currents and line to line voltages at the fault when a double

line to ground fault with Zr= 0 occurs at bus 4.

4. (a) What is the essential difference between plug-setting multiplier and time multiplier

setting? What is the effect of plug setting on electromechanical relay burden?

(b) Explain the principle of impedance type distance relay and its characteristics on R-X plane.

(c) Explain why overcurrent relay is not used for feeder protection.

(d) Discuss the voltage and current behaviour in a circuit breaker after a fault occurs.

SECTION-B


All the symbols have their usual significance.

5. (a) Derive the bus admittance matrix for the system shown in Fig. forQ. No. 5(a).

Yz.R..fZ.j-~IL~~

Herte ..~ -iJ"-hdi.5 b.eM1- LU~ ~.. .

Contd P/3

(6+4)

(10)

(7)

(8)

(10)

••=3=

EEE 305'Contd •.. Q. No.5

(b) Three transformers, each rated 50 MVA, 40/4 kV, are connected /j.-Y with a balanced

load of three 1 ohm, Y-connected resistors. Choose a base of 200 MV A (for, the 3 phase

bank), 100 kV for the high voltage side of the transformer arid specify the base for the

low voltage side. Also, determine the load resistance, RL in ohms referred to the high'

voltage side and per unit ~~lue of this resistance on the two sides of the transformer on

the appropriate base. (18)If now, the base on the high voltage side is changed into 100 MY A (for the 3 phase

bank), 50 kV, what will be the per unit RL on the two sides of the transformer?

(c) For a three winding transformer, derive the expressions for Zp, Zs, Zt when Zps, Zpt

and Zst are available from tests. (7)

6. (a) A power station has to meet the following demand: (20).Group A : 200 kW between 8 am and 6 pm

Group B : 100 kW between 6 am and lOam

Group C : 50 kW between 6 am and lOam

Group D : 100 kW between 10 am and 6 am of the following day

Plot the daily load curve and determine

(i) Diversity factor, (ii) kWh generated per day, (iii) Load factor.

(b) (i) Prove that ab2 - a2b + a3 = 0 where a is symmetrical component operator and b = /.(2x7 ~ =15)

(ii) For three phase system, prove that line-to-line voltages, whether balanced or

unbalanced, have no zero-sequence components.

7. (a) Two transformers, Ta and Tb are connected in parallel to supply an impedance of 1.6

+ j 1.2 per unit at a voltage of 1LO° per unit. Ta has a voltage ratio equal to the ratio of the

base voltages on the two sides of the transformer and has an impedance of jO.l per unit

on the appropriate base. Tb includes both a transformer having the same turns ratio as Ta

and a regulating transformer with a phase shift of 4°. The impedance ofT b is jO.l per unit

on the base of Ta. Find the complex power transmitted to the load through each

transformer. (15)(b) Fig. for Q. No. 7(b) shows a three-bus system with generators at buses 1 and 3. Line

admittances .are marked in per unit on a 100 MVA base. A power flow study of the

system is to be made by the fast decoupled method. Determine the B matrix and

calculate the first-iteration angle corrections in radians. (20)

Contd P/4

=4=

EEE305Contd ... Q. No. 7(b)

LtOO MW

g=-IO,",":,)30

~ I o.c/t. b~.~ =} 'OlJl.2()pl,t(J) .1' ..

~OOMW

8. (a) For the system shown in Fig. for Q. No. 7(b), a Newton-Raphson power flow solution

is to be carried out. Determine the first-iteration Jacobian matrix elements and mismatch

vector (M>, L\Q) elements.

(b) A three-phase fault occurs at bus (2) ofa network having Zhus:

jO.24 jO.l9 j.l5 jO.l4- jO.19 jO.22 j.14 jO.15Zbus =

jO.15 jO.14 j.19 jO.lOjO.14 jO.l5 j.lO jO.l9

Determine the sub-transient current in the fault, the voltages at buses (1) and (3) during

the fault. Neglect all pre-fault currents.

(25)

(10)

L-3/T-l/EEE Date : 24/05/2014BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA

L-3/T-l B. Sc. Engineering Examinations 2012-2013

Sub: EEE 307 (Electrical Properties of Materials)



USE SEPARATE SCRIPTS FOR EACH SECTION

.';; SECTION - A

There are FOUR questions in this section. Answer any THREE.,.,

1. (a) Explain the origin of complexity in relative permittivity. Also derive the expression

forIoss tangent. (15)(b) Draw the equivalent circuit of a Debye dielectric and explain the origin of the

individual components. Briefly explain the Cole-Cole plot in terms of De bye equations. (20)

2. (a) Consider a 1.0 nF polyester capacitor that has a polymer (PET) film thickness of 1.0

~m. Calculate the equivalent circuit of this capacitor at 50°C and at 150°C. Use the data

from Fig. for Q. No. 2(a). (20)

[lEAnrHH)l

~ ,.) I PET:H f= 1Li-l/2 s-j

€' ')'l'1\l'l8 /!' -'. ""'" ...:'r -" '" ..

.~~,6 I

E,

2.5

fI, I

fUJI

..n (IIJI :;

'~

,j

n 5~i I 00 I 5U' 20<) 2,.)fl

If lJ'peratlUe ( lie)

(b) Show that dipolar polarization is given by:

_ 1 p5a.d ---

3 kT[Symbols have their usual meaning]

(15)

3. ,(a) What is the maximum super current that can be passed through 2 mm diameter lead

wire at 5 k? [For Pb, Tc = 7.18 k,Ho = 6.5 x 10-4 Aim]. Also write a brief description of

giant magneto-resistance. (8+8)(b) Explain Meissner effect. In this relation, also explain the physical distinctions

between type-I and type-II superconductors. Write a brief note on the three parameters

defining the limits of superconductivity. . (5+ 10+4)

Contd P/2

EEE307=2= r

4. (a) Samples of Bi ('Xm = -16.6 x 10-5) and Al (Xm = 2.3 x 10-5) are subjected to an

applied magnetic fieltl of 1.0 T in +x~direction. Calculate M and ~M in each sample

[Symbols have their usual meaning]. Which is paramagnetic and which is diamagnetic? - (10)

(b) An isolated water molecule has a permanent dipole Po of 6.1 x 10-30 C.m. Under dc-

conditions, <le of the water plolecule is 4 x 10-40C.m. What is E r of steam at pressures arid

temperatures of (l atm, 100°C) and (10 atm, 400°C), respectively? (Use P = (NINA) RT,

where R = 8.314 J.moCt,k-I and NA = 6.023 x 1023mol-I, and the symbols have their

usual meaning. (18)(c) What is a metamaterial as opposed to a natural material? Briefly mention a few

important applications for meta-materials. (7)

. SECTION-B


Symbolshavetheir usual meanings.

5. (a) Define density of states. Derive an expression of three dimensional (3D) density of states. (15)

(b) The solution to Schrodinger's equation for a particular situation is given by (10)

'P(x) = ~Xo .e-'xoDetermine the probability of finding the particle between the limit of 0 $ x $ 3.0/4.

(c) A one-dimensional infinite potential well with a width of 12 A contains an electron. If

the electron drops from the second energy level to the first, what is the wave length of a. .

photon that might be emitted?

6. (a) Draw the following-

(i) (2 2 0) and

(ii) [1 1 0]

(b) Find the Miller indices of the plane shown in Figure for Q. 6(b).

z;.

-~ - ,- --------------~- --

Contd P/3

(10)

(10)

(5)

I

=3=

EEE307Contd ..• Q. No.6

(c) The electron drift mobility in.silver has been measured to be 56 cm2 V-I 8-1 at 27°C.

The atomic mass and density of Ag are given as 107.87 g moel and 10.5 g cm-3,

respectively. Assuming that each Ag Atom contributes one conduction electron,

(i) Calculate the ;esistivity of Ag at 27°C.

(ii) Calculate the thermal conductivity of Ag at 27°C.

7. (a) Discuss the origin of energy bands in crystal with Kronig-Penney model.

(b) A proton att~mpts to penetrate a rectangular potential barrier of height lOMe V and

thickness 10-14 m. The particle has a total energy of3 MeV. Calculate the probability that

the particle will penetrate the potential barrier.

(Mass of proton mp = 1.67 x 10-27 kg)

8. (a) What is parabolic band approximation?

(b) A photoelectric experiment indicates that violet light of wavelength 420 nm is the

longest wavelength radiation that can cause photoemission of electrons from a particular

photocathode.

(i) What is the work function in eV?

(ii) If a UV radiation of wavelength 300 nm is incident upon the photocathode, what

wil~ be the maximum kinetic energy of the photoemittedelectrons?

(c) The E-K relationship of a material is given by -,

E = Eo - EI cos a. (K- Ko),

where Ko is the value of K at the minimu-.n energy (Eo). Determine the effective mass of

the particle at K =Ko in terms of the equation parameters.

(20)

(20)

(15)

(10)

(10)

(15)

May 12:

May 15:

May 18:

May 20 :

May 22 :

May 24 :

L-31T-l/EEE Date: 31/05/2014BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA

L-3/T-1 B. Sc. Engineering Examinations 2012-2013

Sub: HUM 279 (Financial and Managerial Accounting)

Full Marks: 210 Time ..: 3 Hours


USE SEPARA IE SCRIPTS FOR EACH SECTION


1. (a) Explain the assumptions of Accounting according to Generally Accepted Accounting

Principles (GAAP). (5)

(b) Mount View Motel has the following transaction on May, 2010. (30)May 1: The owner invested Tk. 10,00,000 cash.

May 2: Advertised the business in "Daily Star" for Tk. 15,000 on account.

May 6: Purchased supplies for cash Tk. 60,000

May 10 : Purchased office equipment for Tk. 250,000; paying Tk. 50;000 in cash with the

remaining on account.Provide services and billed client for Tk. 300,000

Withdraw cash for personal use Tk. 10,000

Salary for the month paid in cash Tk. 25,000

Paid balance due to Daily Star.Received from customers on account from May 12 transaction.

Provide services for cash Tk. 20,000 -

Requ.ired:(i) Prepare a tabular summary from the above transaction.

(ii) Prepare an income statement for the month.

2. (a) What is a Trial Balance and what are its purpose? (5)(b) Following are the account balances of Butterfly Computer Services Limited for the

year ended on 30th June, 2012: (14)Purchasing cost of computer Tk. 20,00,000; Sale of computer 34,00,000; Service feesreceived Tk. 300,000; Salaries to hardware engineers Tk. 200,000; Advetisement

expense Tk. 50,000; Office rent Tk. 60,000; Maintainance expense Tk. 130,000;

Accounts payable Tk. 80,000; Tax payable Tk. 5;000; Bad debtsTk. 50,000; Prepaid

insurance Tk. 50,000; Office equipment Tk. 60,000; Discount allowed Tk. 85,000;

Bank balance Tk.455,000; Unpaid salaries Tk. 5,000; Accounts receivable

Tk. 600,000; Opening stock of computer Tk. 400,000; Furniture Tk. 250,000; Capital

Tk.600,000.

Required: Prepare a Trial Balance.

Contd P/2

=2='

HUM 279Contd ••. Q. NO.2

Nikon CompanyIncome statement

ear ended December 31, 2011600,000

(c)• L

For theNet salesExpensesCost of goods soldSelling and administrativeInterest expense. Income tax expenseTotal expenseNet income

415,000120,8007,80018,000

561,60038.400

(16)

Nikon CompanyBalance Sheet

December 31,2011Assets Liabilities and EquityCash 21,000 Accounts payable . 122,000Investment (Short term) 18,000 Income tax payable 23,000Accounts Receivable 86,000 Bond payable 120,000Inven~ory 90,000 Common stock 150,000

(Tk. 5 par) ..

Plant asset , 423,000 Retained earnings 233,000Total asset 638,000 638,000

Other Data: Common stock recently sold at Tk. 19.50 per share.Required: Compute the following ratio -

(i) Acid Test (ii) Receivable turnover (iii) Return on equity (iv) Debt to total asset(v) Earning per share "(vi) Price-earning ratio (vii) Asset turnover or Return on asset(viii) Inventory turnover.

3. (a) Why do we need adjusting entry?

(b) The trial balance ofLG Electronics at January 31,2011 is given below-

LG ElectronicsTrial Balance

January 31,2011Accounts Title Debit (Tk.) Credit (Tk.)Cash .. 12,800Supplies 2,500Prepaid 'insurance 3,000Office equipment 5,000Notes payable ~ 5,000Accounts payable ~ 2,500Unearned revenue 1,200Capital 10,000Drawings 500Service revenue 10,000Salary expense 4,000Utility expense 900

Tota}!' '(28,700 28,700Contd P/3

(5)(30)

=3=;HUM 279Contd ••. Q. No. 3(b)

Analysis reveals the following additional data:

~ Supplies on hand at January 31, Tk. 1200.

~ Insurance policy is for two years.

~ Depreciation Tk. 200 for each month.

~ Unearned revenue is still unearned Tk. 800.

~ Interest accrued at January Tk. 200.

~ Service provided but not recorded Tk. 1200:

Required:(i) Prepare adjusting entries.(ii}Prepare adjusted Trial Balance as on January 31, 2011.

4. (a) Why maya trial balance not contain up-to-date and complete financial information? (5)(b) Following balances are extracted from the ledger balances of Philips Company at 31 st .

December, 2010. (30)Accounts Title Debit (Tk.) Credit (Tk.)Accounts Receivable 12,000Accounts Payable 6,000Cash 30,500Patent 20,000Capital 50,900Supplies 900Salaries 7,000Sales salaries 3,000maintainance expense 4,000Rent 13,000Notes payable 5,000Bond payable I 20,000Tax payable 20,000Store equipment 25,000Machinery

,

2,500Unearned commission 3,000Sales 47,000Cost of goods sold 30,000Prepaid insurance 4,000

151.900 151.900

Adjustments

• Two-thirds of supplies were used during the period.

• 60% of unearned commission was earned during the period.

• Depreciation 10% of store equipment.

• 60% of rent relates to office and the remaining to sales.Required:

(i) Prepare a multiple step (classified) income statement at 31st December, 2010.I

(li) Prepare a statement of owners equity and aiclassified balance sheet at 31st December, 2010.

Contd P/4

=4=

HUM 279SECTION-B

There are FOUR questions in this section. Answer any THREE. ,Symbols indicate their usual meaning.'

5. (a) What is the difference between manufacturing cost and non-manufacturing cost? Giveexample of each. (6)(b) Differentiate among variable, fixed and mixed cost. (3)(c)Givenbelowis the CostDataofZY companyfor the year2013.All the figuresare in Taka. (26)

Beginning Raw Material 80,000Ending Raw Material 60,000Beginning WIP 22,000Ending WIP 18,000Beginning Finished Good 44,000EJ.ldingFinished Good 33,000Material Purchase 60,000Freight charge 3,000 ,Direct Labor Cost 20,000Indirect Labor 10,000Factory machine insurance J 15,000Depreciation Expense:Factory Machine 22,000Office furniture 33,000Factory electricity bill 15,000Sales Salary 24,000Television'promotion 30,000Office repair 8,000Production manager's salary 70,000

Requirements:(i) Prepare a Cost Statement for the year 2013.(ii) Calculate the net income for the company.

6. (a) Tyler Tooling Company uses a job order costing system with overhead applied toproducts on the basis of machine hours. For the upcoming year, the company estimatedits total manufacturing overhead cost at BDT 250,000 and total machine hours at 62,500.During the first month of operations, the company worked on three jobs and recorded the

following actual direct materials cost, direct labor cost and machine hours for each job: (15)Job 101 Job 102 Job 103 Total

Direct material \, 12,000 9,000 6,000 27,000Direct labor cost 18,000 7,000 6,000 31,000Machine hours 2,000 hours 3,000 hours 1,000 hours 6,000 hours

Contd P/5

(.

=5=HUM 279Contd eo. Q. No. 6(a)

Required:(i) Calculate the predetermined overhead rate.

(ii) Calculate the overhead cost for each job.(b) A car company has the two operating departments namely- Machine department and

Car department. It has the following information - (20)Budgeted fixed cost Tk.3000,000

Practical capacity 18,000 machine hoursbudgeted usages by:Machine department 9,000 machine hoursCar department 3,000 machine hours

Actual usages by:Machine department 9,500 machine hoursC.ar department 3,500 machine hoursVariable cost Tk. 200 per hour

RequiredAllocate the cost to the operating departments using

(i) Single rate method(ii) Dual rate method

(iii) Practical capacity method(iv) Which one is the best method? Explain.

7. (a) What is meant by the tern "Operating Cycle"? Define current asset. What basis is

used for arranging individual item within the current assets section? (7)(b) Explain the statement, "Financial statements are designed for analysis". (4)(c) A company is considering an investment proposal to install a new machine at a cost of

Tk. 50,000. The estimated cash flows froni the investment proposal are as follows - (24)Year CFAT (Cash Flow Adjusted Time)

1 10,000

2 10,450

3 11,800

4 12,250

5 16,750

Required: Determine

(i) Pay Back Period

(ii) Internal rate of return (IRR).(iii) Net Present Value (NPV) at 10% cost of capital.(iii) Profitability Index (PI) at 10% discount rate.

Contd P/6

..,::J

=6=HUM 279

8. (a) What is inventory costing? Differentiate between variable and absorption. costing

inventory method. (5)

(b) Explain the criteria for allocating indirect cost to the cost object. (4)

(c) Following data relates to a manufacturing company: (26)

Number of units produced each year

Variable cost per unit:

Direct materials

Direct labor

Variable Manufacturing Overhead

Variable selling and Administrative expenses

FiXed costs per year:

Fixed manufacturing overhead

Fixed selling and administrative expenses

Units in beginning inventory

Units produced

Units Sold

Units in ending inventory

Selling price per unit

6,000

$2

-$4

$1

$3

$30,000

$10,000

o6,000

5,000

1,000

$20

Required:

(i) Calculate the product cost per unit under Absorption costing system and Variable

costing system.

(ii) Prepare income statements using Absorption costing system and Variable costing

system.

(iii) Explain the Reason for difference in net operating income due to change in two

different costing methods.

"

Gr= 311'~4+3= 27--

L-3ff-l/EEE Date: 10/05/2014BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY, DHAKA

L-3/T-l B. Sc. Engineering Examinations 2012-2013

Sub: EEE 303 (Digital Electronics)


The figures in the margin indicate full marks.USE SEPARATE SCRIPTS FOR EACH SECTION


.- --1. (a) Given the function f=,X1X2X4 +X2X3X4 +XIX2X3, a straight forward

implementation in....an FPGA with three-inputs LUTs requires four LUTs. Show how it

can be done using only 3 three-input LUTs. Label the output of each LUT with an

expression representing the logic function that it implements. (12)(b) What logic gate is realized by the circuit shown in Figure l(b). Does this circuit suffer

from any maj0f ~rawbacks? (8)

(c) Draw the transistor level diagram of a PLA circuit using NOR-NOR implementation

which will implement the following functions. (15)

fl = (a + b+ c).(a + b). (b+ c)

f2 = (a + b + ~).'(a + b). (a +~)f3 = Gi + b). (a: + c)

2. (a) The content of a 4 bit shift Register is initially 1101. The register is shifted six timesto the right, with the serial input being 101101. Whads the content of the register after

each shift? (5)(b) Design a four bit Register using D Flip-Flops and 4 to 1 M~ltiplexer with mode

selection inputs Stand So. The register operates according to the following function

table. (15)

8}oo1 .1

SooIo1

Register OperationComplement the four outputsShift LeftClear Register to 0 (Synchronous with the clock)Load Parallel Data

Contd P/2

=2=EEE303Contd ..• Q. No.2

(c) Write the verilog code for the circuit in Q. 2(b). (8)(d) Given a 100 MHz clock signal, derive a circuit using D Flip-Flops to generate 25 MHz

" clock signals. Draw a timing diagram for all clock signals assuming reasonable delays. (7)

3. (a) Design a modulo-12 up counter with synchronous reset. Also write verilogcode for

the counter. (15)(b) A binary ripple counter uses Flip-Flops that trigger on the positive edge of the clock.what will be count if (i) the normal outputs of the flip-flops are connected to the clock?(ii) the complement outputs of the flip-flops are connected to the clock? and (iii) what

happen if negative edge of the clock is usedto trigger counter Flip-:Flops? (12)(c) Define propagation delay, setup time and hold time. For the Flip-Flops in the four bit

counter with parallel-load capability, assume that tsu=3 ns, th = 1 ns and the propagation

delay through a FF is 1 ns. Assume that each AND gate, XOR gate and 2 to 1Multiplexerin 1J?ecounter has the propagation delay equal to 1 ns. What is the maximum clock

frequency for which the .circuit will operate correctly? (8)

4. (a) Derive a CMOS complex gate for the following logic functions. (15)(i) f(XI, X2, X3,)4) = Lm (0, 4,6,8,9, 15)+ D (3, 7, 11, 13)- -

(ii) f = (A + B)(C + D)( A + B +D)Use as few transistors as possible.

(b) Derive the expression for propagation delay of a CMOS inverter when output of the

inverter goes from high to low. Take necessary assumptions if needed. (10).(c) Draw and explain the voltage transfer characteristics ofa CMOS inverter. (5)(d) Consider an eight-input NAND gate built using NMOS technology. If the voltage

drop across each transistor is 0.1 V what is VOL? What is the corresponding NML if

VIL= 1V. (All symbols have their usual meanings.) (5)

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

All symbols have their usual meaning.

5. (a) The output waveform in the Fig. Jor Q. No. 5(a) is incorrect ~or the inputs that areapplied to the circuit. Assuming that one gate in the circuit has failed, with its outputeither an apparent constant HIGH or a constant LOW determine the faulty gate and the

type of failure (output open or shorted). (15)(b) Design a four line to two line priority encoder circuit 'with active high inputs and

outputs, with priority assigned to the higher order data input line. Use NOR gate only for

the circuit implementatfon. (12)

(c) Write a veri1<?gcode for a 4 to 2 priority encoder using the for loop. (8)

Contd P/3

=3=

EEE303

6. (a) Design a digital control logic for controlling the fluid in a storage tan1e The purpose

of the logic is to maintain an appropri~te level of fluid by controlling the inlet and outlet

valves. Also the logic must control the temperature of the fluid within a certain range and

issue an alarm if any of the level or temperature sensors fail. A level sensor failure is

indicated when the high level sensor is active but low-Ie~el sensor is not active. A

temperature sensor failure is indicated when both temperature sensors (hot and cold) are

active at the same time. Four sensors are high level, low level~ high temperature and low

temperature respectively. The output of control logic are Inlet' and Outlet valve, heater

and Alarm. Use minimum number of gate in designing the circuit.

(b) Write verilog code for the controller using assign statement.

(25)

(10)

7. (a) Implement function f, using

(i).4xl MUX

(ii) 2 to 4 Decoder and one AND/OR Gate only

The function is f(xt. X2,X3,X4)= Lm (1,3,4, 11, 12, 13, 14, 15).

(b) Write the verilog code for a 16 to 1mux module }lSingifIogic.

(c) Design a 4x 1MUX using a decoder and tri state buffers.

(20)

(8)

(7)

8. (a) Design a logic circuit to implement a three bit magnitude comparator having on~

output that goes HIGH when the two three bit numbers are equal. Use' NANO' gates only ..

(b) Convert the following

(i) (374.26)8 to binary

(ii) (1110100.0100111)2 to octal

(iii) (17E.F6)16 to binary

(iv) (101100111O.011011101)z to hexadecimal number

(c) Write the veri log code of an n bit adder using concatenate operator.

(15)

(12)

(8)

Ar ..--...._.._-_._.."A 'J--I . I.,.." BB ._: ..rL c

I I IC J . 1---...:r-- D...~1.. _ I

D-rl-.~~I I r'-"'-' £E 1 ~ ., II I

X It ..._.~~.,Ft;]-. faY' ~. '{C). S(a.)

Documents

L-3rr-l/EEE Date: 07/06/2014