6N_22Y11.pdf

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Code No: R22011

II B. Tech II Semester Regular Examinations August - 2014

PROBABILITY AND STATISTICS (Com. to CE, CHEM, PE)

Time: 3 hours Max. Marks: 75

Answer any FIVE Questions

All Questions carry Equal Marks

~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Two marbles are drawn in succession from a box containing 10 red, 30 white, 20 blue and 15

orange marbles, with replacement being made after each drawing. Find the probability that

i) both are white ii) first is red and second is white.

b) A businessman goes to hotels X, Y, Z; 20%, 50%, 30%, of the time respectively. It is

known that 5%, 4%, 8% of the rooms in X, Y, Z hotels have faulty plumbing. What is the

probability that businessman room having fault plumbing is assigned to hotel Z. (8M+7M)

2. Find:

a) The constant K such that

otherwise

xifKxxf

,0

30,)( 2

=

<<= is a probability function

i) Find the distribution function F(x) ii) P(1< X ≤ 2)

b) If the probability density function of X is given by

( )

( )

≤<−

≤<

≤<

=

whereelse

xforx

xfor

xforx

xf

0

322

3

212

1

102

Find the expected value of f(x) = x2

- 5x +3. (8M+7M)

3. a) Wireless sets are manufactured with 25 soldered joints each. On the average 1 joint in 500 is

defective. How many sets can be expected to be free from defective joints in a consignment

of 10000 sets?

b) The mean and variance of binomial distribution are 4 and 3

4 respectively. Find P(x ≥ 1).

(8M+7M)

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Code No: R22011

4. Determine the mean and standard deviation of sampling distribution of variances for the

population 3, 7, 11, 5 with n = 2 and sampling is with replacement. (15M)

5. a) A random sample of 400 items is found to have mean 82 and S.D. of 18. Find the maximum

error of estimation at 95% confidence.

b) Measurements of the weights of a random sample of 200 ball bearings made by a certain

machine during one week showed a mean of 0.824 and a S.D. of 0.042. Find maximum

error at 95% confidence and 90% confidence and 90% confidence interval. (7M+8M)

6. a) Explain the procedure generally followed in testing of hypothesis.

b) Write short note on Type I and Type II error. (8M+7M)

7. Four coins were tossed 160 times and the following results were obtained.

No. of heads 0 1 2 3 4

No. of Frequencies 17 52 54 31 6

Under the assumption that coins are balanced, find the expected frequencies of 0, 1, 2, 3 or 4

heads, and test the goodness of fit (α = 0.05) (15M)

8. An E-Seva Kendra in a Small town has only one bill receiving window with a cashier handling

the cash transaction and giving receipts. He takes on average 5 minutes per customer. The

customers come at random with an average of 8 per hour and the arrivals are Poisson in nature.

Determine:

i) Average queue length

ii) Expected idle time of the cashier

iii) Expected time a new arrival Spends in system.

iv) Expected waiting time of a new arrival before his service is started.

v) Probability that a person has to spend for at least 10 minutes in the system.

[ ]hourperH 108 == µλ ,:int (15M)

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Code No: R22011






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) For any three arbitrary events A, B, C Prove that

P(A ∪ B ∪ C) = P(A)+P(B)+P(C) – P(A ∩ B) – P(B ∩ C) – P(C ∩ A) + P(A ∩ B ∩ C).

b) State and prove Baye’s Theorem. (8M+7M)

2. a) If probability density function

( ) .,0

303

≤≤

=elsewhere

xinKxxf

Find the value of K and find the probability between 2

1=x and

2

3=x .

b) A random variable X has the following probability distribution

X: 1 2 3 4 5 6 7 8

f(x) K 2K 3K 4K 5K 6K 7K 8K

Find the value of i) K ii) P(x ≤ 2) iii) P(2 ≤ x ≤5) (7M+8M)

3. a) If the probability is 0.05 that a certain wide-flange column will fill under a given axial load.

Find: i) at most two will fail ii) at least four will fail

b) If the chance that any of the 10 telephone lines busy at an instant is 0.2. What is the most

probability of this number. (8M+7M)

4. Samples of size 2 are taken from the population 1, 2, 3, 4, 5, 6 with replacement. Find:

i) The mean of the population

ii) Standard deviation of the population

iii) The mean of the sampling distribution of means.

iv) The standard deviation of the sampling distribution of means. (15M)

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Code No: R22011

5. a) A random sample of 400 items is found to have mean 82 and S.D. of 18. Find the maximum

error of estimation at 95% confidence. Find the confidence limits for the mean if X = 82?

b) Measurements of the weights of a random sample of 200 ball bearing made by a certain

machine during one week showed a mean of 0.824 and a S.D of 0.042. Find maximum error

at 95% confidence. Find the confidence limits for the mean if X = 32? (7M+8M)

6. a) What is meant by Level of Significance?

b) Write the formula for testing the hypothesis concerning “Two Means”? (7M+8M)

7. Eight students were given a test in a STATISTICS and after one month coaching they were

given another test of the similar nature. The following table gives the increase in marks in the

second test over the first.

Do the marks indicate that the students have gained from the coaching? (15M)

8. A manager of a local hamburger restaurant in preparing to open a new fast food restaurant

called Hasty Burgers. Based on the arrival rates at existing outlets. Manager expects customers

to arrival at the drive in window according to a Poisson distribution, with a mean of 20

customers per hour. The service rate is flexible, however, the service time is expected to

following an exponential distribution. The drive in window is single ever operation.

a) What service rate is needed to keep average number of customers in the service system to 4?

b) For the service rate in part (a), what is the probability that more than 4 customer are in the

line and being served? (15M)

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Student No. 1 2 3 4 5 6 7 8

Increase of Marks 4 -2 6 -8 12 5 -7 2

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Code No: R22011






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) An anti-craft gun can take a maximum of 4 shots at an enemy plane moving away from it.

The probabilities of hitting the plane at the first, Second, third and fourth shots are 0.4, 0.3,

0.2 and 0.1 respectively. What is the probability that the gun hits the plane?

b) Suppose 5 men out of 100 and 25 women out of 10, 000 are color blind. A color blind

person is chosen at random. What is the probability of the person being a male? (Assume

male and female to be in equal numbers). (7M+8M)

2. a) A sample of 4 items is selected at random from a box containing 12 items of which 5 are

defective. Find the expected number E of defective items.

b) X is a continuous random variable with probability density function given by

>><<−−−

=otherwise

BxforB

xKxxf

,0

0,0,10,1)1(1)(

αα

Find K and mean value of X. (7M+8M)

3. a) If the chance that one of the ten telephone lines is busy at an instant is 0.2.

i) What is the chance that 5 of the lines are busy?

ii) What is the most probable number of busy lines and what is the probability of this

numbers?

iii) What is the probability that all the lines are busy?

b) Fit a binomial distribution to the following frequency data. (8M+7M)

4. a) A random sample of size 64 is taken from a normal population with µ = 51.4 and S = 68.

What is the probability that the mean of the sample will

i) Exceed 52.9 ii) Fall between 50.5 and 52.3 iii) Be less than 50.6.

b) Out of 600 articles selected at random from a batch of 10,000articles and 35 were found to

be defective. How many defective articles would you reasonably except to have in the whole

batch? (7M+8M)

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x 0 1 2 3 4

y 28 62 46 10 4

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Code No: R22011

5. The mean mark in mathematics in a common entrance test will vary from year to year. If this

variation of the mean mark is expressed subjected by a normal distribution with mean µ0 = 72

and variance 76.52

0 =σ . i) What probability can we assign to the actual mean mark being

somewhere between 71.8 and 73.4 for the next year’s test. ii) Construct a 955 Bayesian interval

for m if the from the next incoming class yielding a mean mark of 70 with S.D. of 8. iii) What

posterior probability should we assign to the event of part (i). (15M)

6. a) Random samples of 400 men, and 600 women were asked whether they would like to have a

flyover near their residence. 200 men and 325 women were in favor of the proposal. Test the

hypothesis that proportions of men and women in favor of the proposal are same, at 5%

level.

b) In a city 250 men out of 750 were found to be smokers. Does this information support the

conclusion that the majority of men in this city are smokers? (8M+7M)

7. a) A group of 5 patients treated with medicine. ‘A’ weigh 42, 39, 48, 60 and 41 Kgs. Second

group of 7 patients from the same hospital treated with medicine ‘B’ weigh 38, 42, 56, 64,

68 69 and 62 Kgs. Do you agree with the claim that medicine B increases the weight

significantly?

b) Memory capacity of 10 students was tested before and after training. State whether the

training was effective or not from the following scores. (8M+7M)

Before

Training 12 14 11 8 7 10 3 0 5 6

After

Training 15 16 10 7 5 12 10 2 3 8

8. Patients arrive at a clinic according to a Poisson distribution at the rate of 30 patients per hour.

The waiting room can not accommodate more than 13 patients not including the one that is

examine? Examination time per patients is exponential with mean rate 20 per hour.

i) Find the effective arrival rate at the clinic.

ii) What is the probability that an arriving patient will not wait. What is the probability that he

finds a vacant seat in the room.

iii) What is the expected waiting time until the patient is discharged from the clinic. (15M)

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Code No: R22011






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1. a) Among 100 students 50 are studying Mathematics, 30 are studying Physics, and 20 are

studying Mathematics and Physics. If a student is chosen at random find the probability that

the student is

i) studying Mathematics or Physics ii) studying neither Physics nor Mathematics.

b) The probability that three men hit a target respectively are 1/5, 2/3 and 1/4. Find the

probability that two shots hit the target. (8M+7M)

2. a) The cumulative distribution function for a continuous random variable X is

( )

<

≥−=

−

0,0

0,1 2

x

xexF

x

Find: i) the density function f(x), ii) mean and iii) variance of the density function

b) A sample of 3 items is selected at random from a box containing 10 items of which 4 are

defective. Find the expected number of defective items? (8M+7M)

3. a) Prove that Poisson distribution is limiting case of binomial distribution.

b) If an auditor selects 5 returns from among 15 returns of which 9 contain illegitimate

deduction, what the probability that a majority of the selected returns contains illegitimate

deductions? (7M+8M)

4. a) The average marks scored by 32 boys are 72 with a S.D of 8. While that for 36 girls is 70

with a S.D of 6. Does this indicate that the boys perform better than girls at level of

significance 0.05?

b) Out of 500 articles selected at random from a batch containing 10000 articles and 30 were

found to be defective. How many defective articles would you reasonably expect to have in

the whole batch? (7M+8M)

5. a) Determine 99% confidence interval for the mean of contents of soft drink bottles if contents

of 7 such soft drink bottles are 10.0, 10.4, 9.8, 10, 9.8, 10.2,9.6 ml.

b) A sample of cam shafts intended for use in gasoline engines has an average eccentricity of

1.02 and a standard deviation of 0.044 inch. Assuming the data may be treated a random

sample from a normal population; determine a 95% confidence interval for the actual mean

eccentricity of a cam shaft? (7M+8M)

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Code No: R22011

6. a) Among 900 people in a state 90 are found to be chapatti eaters. Construct 99% confidence

interval for the true proportion.

b) In a random sample of 400 industrial accidents, it was found that 231 were due at least

partially to unsafe working conditions construct a 99% confidence interval for the

corresponding true proportion. (7M+8M)

7. Two random samples are drawn from two normal populations as follows:

A 17 27 18 25 27 29 13 17

B 16 16 20 27 26 25 21

Test whether the samples are drawn from the same normal population. Use a 0.05 level of

significance. (15M)

8. Arrivals at a telephone booth are considered to be Poisson, with an average time of 10 between

on arrival and the next. The length of a phone call assumed to be distributed exponentially with

mean 3 minutes, then

i) What is the probability that a person arriving at the booth will have to wait?

ii) What is the average length of the queues that form from time to time?

The telephone department will install a second booth when convinced that an arrival would

expect to have waited at least three minutes for the phone. By how much must the flow of

arrivals be increased in order to justify a second booth? (15M)

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Code No: R22025

II B. Tech II Semester Supplementary Examinations, August - 2014

ELECTRICAL CIRCUIT ANALYSIS - II (Electrical and Electronics Engineering)


Answer any FIVE Questions All Questions carry Equal Marks ~~~~~~~~~~~~~~~~~~~~~~~~

1. a) For a star connected three phase system, derive the relationship between the i) phase

voltages and line voltages ii) phase currents and line currents

b) A balanced delta connected load takes a line current of 15 A when connected to a

balanced three phase 400 V system. A wattmeter with its current coil in one line and its

potential coil between the two remaining lines read 2000 W. Determine the load impedance.

2. The following impedances are connected in the form of a star connected unbalanced system

and it is connected to a 400 V, 3-Ø supply: , 304 0 Ω∠=RZ , 205 0 Ω∠=YZ

. 010 0 Ω∠=BZ Calculate the line currents by using i) loop method ii) Star-delta

transformation technique.

3. For the circuit shown in Figure 3. Find i1(t) and i2(t) for t > 0. Assume zero initial conditions.

4. A series RL circuit with R=50 ohms and L= 0.2 H has a sinusoidal voltage source

)sin(500t 20 φ+ applied at time when 0=φ . i) Find the expression for current ii) At what

value of φ must the switch be closed so that the current directly enter steady state.

5. a) Express y-parameters in terms of h-parameters and ABCD-parameters.

b) Find the y-parameters for the network shown in Figure 5.

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V2

Figure 5

2Ω

1Ω 3V1

2Ω

+ -

V1

I1 I2

SET - 1 R10

+

-

t=0 0.6 H

0.4 H

0.6 H 8Ω

12 Ω

10 V

Figure 3

+

-

t=0 8Ω

8Ω 10 V

Figure

i1(t) i2(t)

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Code No: R22025

6. a) Two 2-port networks N1 and N2 are connected in parallel. The z-parameters of N1 and N2 are

=

43

311NZ and

=

87

752NZ . Determine z-parameters of combined parallel 2-port

network.

b) Derive the ABCD parameters for the network shown in Figure 6 as a connection of two

identical networks.

7. a) Explain about the exponential Fourier series.

b) Obtain the trigonometric Fourier series for the waveform shown in Figure 7. Write down the

amplitude and phase spectrum.

8. a) Explain the properties and applications of Fourier transform.

b) Determine the Fourier transform of the signum function.

2 of 2

Vm

Figure 7

t T T/2 0 T/4

T/2

T

Vm

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V2

Figure 6

2Ω 2Ω 4Ω

V1

I1 I2

1 F 1 F

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Code No: R22025





1. a) Explain how the reactive power is measured in a 3-phase balanced system.

b) In a three phase balanced load, each arm consists of a resistor of 20 ohms, an inductance of

0.5 H and a capacitor of 120 µF connected in series. The supply is a balanced 3-phase 415

V, 50 Hz. Calculate the line current, total power consumed in the load when the three arms

are connected in star and delta.

2. A 400 V, 3-phase supply is connected to an unbalanced load having three impedances

of , 34 Ω+= jZ R , 34 Ω−= jZY . 5.2 Ω=BZ Also . 13.0 Ω+= jZ N Find phase currents,

voltage across loads and neutral current.

3. a) In the circuit shown in Figure 3(a), the switch S is in position 1 for 0.01 seconds and then

changed to position 2. Find the time at which the current is zero and reversing its direction.

b) In the circuit shown in Figure 3(b), find the time when the voltage across the capacitor

becomes 25 V, after the switch is closed at t=0.

4. a) A sinusoidal voltage t100sin )( πVtv = is applied at t = 0.01 seconds to a series R-L circuit,

where R=10 ohms and L=0.1 H. Calculate the ratio of maximum value of current (to which

it rises) to the steady state value of current.

b) A series R-C circuit, with R=50 ohms, C=10 µF has a sinusoidal voltage of 314tsin 2230 .

Find the transient response.

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5Ω

Figure 3(a)

0.1 H 100 V

+

- +

-

S 1

2

20 V

20Ω

Figure 3(b)

1µF 100 V

+

-

S

t=0

i(t)

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Code No: R22025

5. a) Why Z-parameters are known as open circuit parameters and Y-parameters are known as

short circuit parameters? Explain.

b) Find the h-parameters of the following network shown in Figure 5.

6. Find the y-parameters for the network shown in Figure 6 by considering it to be a parallel

combination of a resistive network referred to as Na and a capacitive network referred to as Nb.

7. In the circuit shown in Figure 7, the input voltage is a periodic signal with period 2 as shown.

Determine: i) the exponential Fourier series representation of input signal ii) the trigonometric

Fourier series representation of input signal iii) the exponential Fourier series representation of

output signal

8. a) Determine the Fourier Transform of unit impulse function.

b) Determine the Fourier transform of the rectangular function shown in Figure 8.

2 of 2

f(t)

A

t a -a

Figure 8

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V2

Figure 5

CA

RA mI1

RB V1

I1 I2

Figure 6

1

-j1Ω

1Ω

-j1Ω

-j1Ω

11 21

2

Figure 7

1 H

Vin(t) +

- 1Ω Output

Vin(t)

1

t 2 1 3 4

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Code No: R22025





1. a) For a Delta connected three phase system, derive the relationship between the i) phase

voltages and line voltages ii) phase currents and line currents

b) Three identical coils each having a resistance of 20 ohms and a reactance of 20 ohms are

connected in star and delta across 440 V three phase supply. Two wattmeters are connected

in the system to measure power. Calculate line current and reading in each wattmeter when

the loads are connected in star and delta.

2. A three phase 400 V star connected balanced supply is connected to star connected three load

of ,0 25 0 Ω∠ ,02 11 0 Ω−∠ and ,01 15 0 Ω∠ Find line current, power and current in neutral

of the (i) four wire system (ii) three wire system. Assume zero neutral impedance.

3. For a network is shown in Figure 3, find the currents i1(t) and i2(t) after switching. Initial

potential of capacitor is 4 V and initial currents through the inductor and capacitor are zero.

4. a) Determine the transient and steady state currents through a series R-C circuit when it is

connected to a sinusoidal voltage source.

b) Find the expression for current at t > 0 when switch S is moved from 1 to 2 position at t=0 in

Figure 4(b). Assume a steady state current of 1 A in the R-L circuit when the switch is

moved from position 1 to 2.

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+

-

t=0 1Ω

Figure 3

+

-

1 H

1Ω

10 u(t)

i1(t) i2(t) 1F 4 V

+

-

1Ω

100 Ω

Figure 4(b)

0.1 H 100 sin 100πt

S

1

2

~

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Code No: R22025

5. a) Explain the concept of reciprocity and symmetry. Derive the above condition for h and

ABCD parameters.

b) Obtain the Z parameters of the network shown in Figure 5.

6. a) The h-parameters of certain two-port network are

−=

2.020

210h . Find the new h-parameters

that result, if a 1 ohm resistor is connected in series with i) input terminals of the network

ii) output terminals of the network.

b) Two 2-port networks A and B are connected in parallel. Each of these networks has their

own y-parameters. Show that resultant y-parameters of the combined parallel network is

sum of y-parameters of the individual networks A and B.

7. Determine the current i(t) flowing through the circuit shown in Figure 7.

8. a) Determine the Fourier transform of the triangular function shown in Figure 8.

b) State and explain four properties of Fourier transform.

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f(t)

A

t T0

Figure 8

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Figure 5 - -

V2 V1 3Ω 2I1

1Ω + +

I1 I2

Figure 7

t

1.0

0

π

-1.0

2π ~

1F i(t)

V(t) 1Ω

V(t)

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Code No: R22025





1. a) Compare a three phase star connected system with a delta-connected system. Discuss merits

and demerits of the two systems.

b) Show that power consumed by three identical phase loads connected in delta is equal to

three times power consumed when phase loads are connected in star.

2. a) Explain how the three-phase power is measured using two-wattmeter method.

b) A 100 V, 3-Ø balanced supply is connected to an unbalanced delta load having three

impedances , 90106 0 Ω−∠=ABZ , 56.7125.63 0 Ω∠=BCZ . 100 Ω=CAZ Calculate line

currents and power consumed if (i) the phase sequence is ABC (ii) the phase sequence ACB.

3. In a series RLC circuit L=1 H, and C=1 F. A DC voltage of 20 V is applied at t=0. Obtain i (t)

when i) R=5 ohms, ii) R=2 ohms, iii) R=1 ohm.

4. Find the current i(t) in the network shown in Figure 4 for t>0. At t=0- the network was

un energized.

5. a) For a network, the equations are

212

211

2.0

2.05.0

VVI

VVI

+−=

−=

Find Z and ABCD parameters.

b) Find Y and Z parameters of the network shown in Figure 5.

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V2

Figure 5

3Ω 2Ω

V2 2Ω

+ -

V1

I1 I2

SET - 4 R10

0.1 H

100 sin314t ~

2 F

10Ω

Figure 4

t=0

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Code No: R22025

6. Determine the Y parameters of the two-port network shown in Figure 6.

7. a) Explain about the trignometric form of Fourier series.

b) A voltage

∞++++= .....

5

10sin

3

6sin

1

2sin4)(

ttttv

πππ

πis applied to a circuit consisting

of resistance R=4 ohms in series with an inductance of π

1=L H. Calculate the current in the

circuit.

8. Determine the Fourier transform of the function shown in Figure 8.

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V2

2Ω 2Ω +

V1

I1 I2

1 F

2 F

Figure 6

1Ω

1 F

+

- -

f(t) A

t T -T

-A

0

Figure 8

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Code No: R22029

II B. Tech II Semester Regular/Supply Examinations August - 2014

ELECTRICAL CIRCUIT ANALYSIS - II

(Electrical and Electronics Engineering) Time: 3 hours Max. Marks: 75


1. a) A balanced delta connected three phase load absorbs a complex power of 100kVA with a

lagging power factor of 0.8 when the rms line to line voltage is 2400V. Calculate the

impedance of each arm of the delta connected load.

b) The three rms phase voltages of a balanced 3 ph supply are 00100∠=AnV ,

0120100 −∠=BAnV and 0240100 −∠=CnV . What are the magnitudes of line voltages? If a

balanced 3 phase star connected load of impedance 03010∠ ohms per phase is connected to

the supply, what are the line and phase currents. (8M+7M)

2. A delta connected load with impedance 03010∠=ABZ ohms, 0025∠=BCZ ohms, and

03020 −∠=CAZ ohms is connected to a three phase three wire 500V system. If the phase

sequence is ABC, calculate the line currents and the total power. (15M)

3. Derive the expression for transient response in series R-L-C circuit for DC excitation. Obtain

the solution using Laplace transforms. (15M)

4. In the Figure 1, determine complete solution for current, when switch K is closed at t = 0 for

applied voltage v (t) 400 cos (500t+π/4). Derive the expression for the current. (15M)

1 of 2

R10 SET - 1

~

i

400 cos (500t +4

π)

K

3 µF

15 Ω 0.2H

Figure 1

t = 0

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Code No: R22029

5. a) Find the ABCD parameters for the following network in Figure 2

b) Explain about reciprocity and symmetry in h-parameter representation. (8M+7M)

6. a) Synthesize the impedance function ( )( )3

682

24

+

++=

ss

sssz by Foster form I.

b) Determine where the function ( )133

423

2

+++

+=

sss

ssF is positive real or not. (8M+7M)

7. a) Determine the average power supplied to the circuit shown in Figure 3.

0 0i(t) 2 cos(t 10 ) 6cos(3t 35 )A= + + + +

b) Find the Fourier series of a rectified half sine wave is defined over one period (9M+6M)

f(t) = A sin wt for 0 < t < T/2 and f(t) = 0 for T/2 < t < T.

8. a) State and explain Fourier integral theorem.

b) Use the defining integral to find the Fourier transform of the following function (5M+10M)

( )A / 2 t 0

f t A 0 t / 20 elsewhere

− −τ ≤ <= < ≤ τ

2 of 2

SET - 1 R10

Figure 3

i(t) v(t)

+

-

2 F 10 ohm

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Code No: R22029





1. a) Prove that the line currents are equal to 3 times the phase currents in a delta connected

system and they lag by 300 to the respective phase currents.

b) Explain how reactive power can be measured in balanced three phase systems. (8M+7M)

2. A balanced 3 phase, 3 wire 50 Hz 100 volt supply is given to a load consisting of three

impedances (1+i1), (1+j2) and (3+j4) ohms connected in star as shown in Figure 1. Compute

the voltages across and currents in the three phases of the load using a) Milliman’s theorem

b) Loop current method. Phase sequence ABC. (15M)

3. a) A series RC circuit consists of resistor of 10Ω and capacitor of 0.1F as shown in Figure 2. A

constant voltage of 20V is applied to the circuit at t=0. Obtain the current equation.

Determine the voltages across the resistor and the capacitor.

b) In the Figure 3, determine the current i(t) when the switch is changed from position 1 to2 at

t = 0. (8M+7M)

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ZA=1+j1

VBn =100∟-120˚

VAn =100∟0˚

VCn =100∟-240˚

A

Figure 1

B

C

ZB=1+j2

ZC=3+j4

IA

IB

IC

n n'

10 Ω

0.1F

S

Figure 2

i 20 V

10 Ω

10 V

i (t)

50 V 0.5H

1

2

Figure 3

t=0

t=0

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Code No: R22029

4. Derive the complete solution for transient response in series R-L circuit for AC excitation

(15M)

5. a) The z-parameters of a two port network are z11=20Ω, z22=30Ω, z12=z21=10Ω. Find Y and

ABCD parameters.

b) Derive the condition of reciprocity for ABCD-parameters. (10M+5M)

6. a) Find the Foster form II of the given function ( )ss

sssZ

4

1582

2

+

++=

b) Synthesize the RL driving point impedance by using Cauer second form ( )148

4822

2

++

++=

ss

sssZ

(7M+8M)

7. The circuit shown in Figure 4, has a non-sinusoidal vs(t) source that has Fourier series

( ) ( )s

k 1

1 2 1v t sin n t

2 n

∞

=

= + ππ∑ for n = 2k -1. Find the voltage vo(t) at inductor and the

corresponding amplitude spectrum. (15M)

8. a) Determine the output voltage across the capacitor if the excitation is a current source

i(t) = e-t u(t) in below Figure 5.

b) Suppose the input given to a linear system is v = 2e-t u(t). Determine the response of the

system (9M+6M)

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SET - 2 R10

+

V0 (t)

-

2 H

5 ohm

vs(t)

Figure 4

Figure 5

i (t)

+

V (t)

-

1 F 2 Ω

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Code No: R22029





1. a) Three impedances each of 3-j4Ω are connected as shown in Figure 1 across a 3ph 230V balanced supply. Calculate the line and phase currents in the delta connected load.

b) A balanced 3 ph load draws 100kW at a lagging power factor of 0.8 from a 400V 3 phase

50Hz main. Calculate the complex power and the line current. (9M+6M)

2. A three phase 4-wire 400volts a.c. system supplies a star connected load in which 0010∠=AZ

Ω, 03015∠=BZ Ω, and 03010 −∠=CZ Ω. The phase sequence is ABC. A wattmeter W1 has

its current coil in phase A and its pressure coil across A and B. Another wattmeter W2 has its current coil in phase C and its pressure coil across B and C. Calculate the wattmeter readings and the current through the neutral wire. Also calculate the voltage between supply neutral and load neutral. (15M)

3. a) In an RL circuit of Figure 2, the switch closes at t = 0. Find the complete current response if R =10Ω, L=0.01H;

b) A 200Ω resistor is in series with an inductor L. The initial value of the inductor current is 5 mA and its value 5ms later is 3mA. Find the time constant and the inductance. (8M+7M)

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IA

Figure 1

A

B

C

IB

IC

IBC ICA

3 –j4

3 –j4 3 –j4 IAS 230V, 50Hz

3ph Supply

Sw

v(t) = 10 V

i(t)

t= 0 R

L

Figure 2

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Code No: R22029

4. In the Figure 3, determine complete solution for current, when switch K is closed at t = 0. For

applied voltage is V(t) which is given as 100 cos (103t+π/2). Derive the expression for the

current. (15M)

5. Find z-parameters for the given network shown in figure 4 using interrelations. (15M)

6. a) Synthesize the function Z(s) using first Foster form of realization ( )( )

( ) ( ).164

1022

2

++

+=

ss

sssZ

b) Synthesize the LC impedance function ( )( ) ( )

( ).2

312

22

+

++=

ss

sssZ in II cauer form.

7. a) Determine the complex Fourier series for the waveform shown in Figure 5. b) In a two-element series network voltage and current are given as v = 40+30 sin 314 t + 30 sin 942 t i = 8 sin (314 t +600) + 15 sin (942 t + 450) Determine the power consumed and the network elements. 8. a) Use the defining integral to find the Fourier transform of the following function

≥

<=

− atte

ttf

at ,)(

0

00

b) For the circuit shown in Figure 6, find v0 (t) if v0 (t) = 5 e-3t u(t).

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K

100 cos (103 t +2

π)

t= 0

R = 20Ω

L

Figure 3

i

L = 0.1H ~

Figure 4

L L

C C

C

I1 I2

V1 V2

L

+ +

_ _

f(t)

T/2

A

- A

0 t

-T/2

Figure 5

T/4

Figure 6

vi (t)

+

V0 (t)

- 4 Ω

1 H

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Code No: R22029





1. a) A balanced three phase inductive load is connected to a balanced 3ph power system. The line

voltage is 480V and the line current is 10A. The angle of the phase impedance of the load is

600. Find the complex power S and real power P absorbed by the load.

b) Three inductors each of resistance 2 ohms and an inductive reactance of 8 ohms are

connected in star and supplied from three phase 230V 50 Hz supply .What are the line and

phase currents and voltages? Also calculate the power input and power factor. (7M+8M)

2. For the network of Figure 1, calculate the line currents and power consumed if a) the phase

sequence is ABC and b) the phase sequence is ACB. (15M)

3. a) The circuit shown in Figure 2 consists of resistance, inductance and capacitance in series

with a 100V constant source when the switch is closed at t=0. Find the current transient.

b) In the circuit shown in Figure 3, obtain the equations for i1(t) and i2(t) when the switch is

closed at t = 0 (7M+8M)

4. Derive the expression for transient response in series R-L-C circuit for AC excitation using

Laplace transforms (15M)

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IA

Figure 1

A

B

C

IB

IC

IBC

ICA

5Ω

2 –j2 Ω

3 +j4 Ω

IAB 100V, 50Hz

3ph Supply

R

20 µF

S

Figure 2

i

100 V

0.05 H L

C

20 Ω t=0 t=0

1 H

10 Ω

S

Figure 3

i1 50 V 20 Ω i2

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Code No: R22029

5. a) Derive z-parameters in terms of y and ABCD parameters.

b) Determine h-parameters after writing transformed network for the given circuit in Figure.4

(10M+5M)

6. a) Synthesize the RC impedance using first Foster form ( )( ) ( )

( ).4

624

+

++=

ss

sssZ .

b) Test whether the function

+

+

ss

s

4

13

2

is positive real. (8M+7M)

7. Find the response io(t) in the circuit shown in Figure 5 if the input voltage v(t) has the

Fourier series expansion ( ) ( )n

2n 1

2( 1)v t 1 cos nt n sin nt

1 n

∞

=

−= + −

+∑

(15M)

8. a) For the circuit shown in Figure 6, find v0 (t) if vi (t) = cos 2 t.

b) List out any six properties of Fourier transform. (9M+6M)

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1F 1F I2 I1

V1 V2

1

11 21

2

1H

Figure 4

4 ohm 2 ohm

2 ohm2 H v(t)

i0(t)

Figure 5

Figure 6

vi (t)

+

V0 (t)

- 5 Ω

1 H

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Code No: R22031

II B. Tech II Semester Regular Examinations, August - 2014

MECHANICS OF SOLIDS (Com. to ME, AME, MM)




~~~~~~~~~~~~~~~~~~~~~~

1. a) Define Bulk modulus. Derive a relation between young's modulus of elasticity and bulk

modulus.

b) An assembly of a steel bar of 70 mm diameter enclosed in an aluminium tube of 80 mm

internal diameter and 120 mm external diameter is compressed between two rigid parallel

plates by a force of 400 kN. The length of the assembly is 1 m. Determine the stresses in the

tube and the bar if the young's modulii of elasticity of steel and aluminium are 200 GPa and

80 GPa respectively. (7M+8M)

2. a) Derive the relation between shear force and rate of loading.

b) Draw shear force and bending moment diagrams for a beam of 6 m long and loaded as

shown in Fig.1 and indicate the main values. (4M+11M)

15 kN10 kN

1 m

1 m3 m 2 m

A

B C

D

Fig. 1

3. a) What are the assumptions made in the theory of simple bending?

b) A simply supported beam made of cast iron has a length of 1 m and a square cross section of

20 mm size. The beam fails on applying a load of 400 N at mid span. Find the maximum

uniformly distributed load that can be applied safely to a 50 mm wide x 80 mm deep cross

section and 1.5 m long cantilever made of the same material as that of the simply supported

beam. (4M+11M)

4. a) What are the assumptions taken in the analysis of shear stress in beams?

b) Determine the maximum shear stress in a beam with rectangular cross-section of depth D

and width B if a shear force F acts on the section. Also compare it with its mean shear

stress. (4M+11M)

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Code No: R22031

5. a) What are statically determinate and statically indeterminate frames?

b) Determine the forces in all the members of the frame shown in Fig. 2. Use method of joints.

(4M+11M)

75 kN

8 m

4 m

4 m

B

D

FE

C

A

Fig. 2

6. a) Derive the differential equation for the elastic line of a beam subjected to deflection.

b) Obtain the deflection equation for the beam shown in Fig. 3. The length of the beam is L and

the flexural rigidity is EI. Use Macaulay's method. (15M)

W

a b

A B

Fig. 3

7. a) Drive an expression for volumetric strain in a thin cylinder subjected to an internal pressure

p. The ends of the cylinder are closed by circular plates.

b) A thin cylinder of 250 mm inside diameter and 3 mm thick has its ends closed by rigid

plates. It is filled with water under pressure. If an external axial pull of 50 kN is applied to

the ends, the water pressure falls by 0.1 MPa. FInd the value of poisson's ratio if the bulk

modulus is 2000 MPa young's modulus is 150 GPa. (5M+10M)

8. A steel cylinder of 300 mm external diameter is to be shrunk on to another steel cylinder of 150

mm internal diameter. After shrinking, the diameter at the junction is 250mm and radial

pressure at the common junction is 30 N/mm2. Find the original difference in radii at the

junction. Take young's modulus as 200 GPa. (15M)

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Code No: R22031






~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the relationship among the three elastic modulii.

b) A composite bar made up of aluminium and steel is rigidly attached to the end supports as

shown in Fig 1. Find the stresses in the two portions of the bar when it is heated to a

temperature of 80oC from 20

oC when (i) the ends do not yield (ii) the ends yield by 0.3 mm.

The young's modulii of elasticity for steel and aluminium are 200 GPa and 80 GPa

respectively. Coefficients of expansion for steel and aluminium are: Co

steel/.

610 x 711 −

=α

and Co

iumalu/.min

610 x 423 −

=α ; Cross sectional areas of aluminium bar and steel bar are

250 mm2 and 375 mm

2 respectively. (7M+8M)

Aluminiumsteel

450 mm 900 mm

Fig. 1

2. Draw shear force and bending moment diagrams for the beam shown in Fig. 2. Determine the

magnitudes and locations of maximum bending moment for the portions of the beam AB, BC

and CD. (15M)

16 kN/m12 kN

16 kN/m

3 m 2 m 3 m

AB

CD

Fig. 2

3. Derive the bending equation according to the theory of simple bending. (15M)

4. A 60 mm wide and 120 mm deep I-beam is acted upon by a shear force of 10 kN. The web

thickness is 4 mm and the flange thickness is 6 mm. Determine the tranverse shear stress

neutral axis and at the top of the web. Also find the ratio of the maximum shear stress to the

mean stress based on the assumption of uniform distribution over the web. What is the

percentage of shear force carried by the web? Take the moment of inertia of the section as

2.2 x 106 mm

4 and the area is 960 mm

2. (15M)

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Code No: R22031

5. a) Explain the terms: i) perfect frame ii) deficient frame iii) redundant frame

b) Determine the forces in all the members of the frame shown in Fig. 3.Use method of joints.

(3M+12M) 60 kN

4 m

4 m

4 m

B

D

FE

C

A

Fig. 3

120 kN

4 m

H

G

6. A simply supported beam of length L carries a concentrated load of P at a distance L1 from one

end. Determine i) the deflection under the load ii) maximum deflection iii) slopes at the two

ends. Use Moment-area method. (15M)

7. a) A spherical tank for storing gas under pressure is 30 m in diameter and is made of structural

steel of 20 mm thick. The yield strength of the material is 250 MPa and the factor of safety

is 2.5. Determine the maximum permissible internal pressure, assuming the welded seams

between various plates are 80 percent as strong as the solid metal.

b) A copper tube of 75 mm internal diameter, 1 m long and 3 mm thick is filled with water

under pressure. Find the change in pressure if additional volume of 3000 mm3 of water is

pumped into the tube. Assume that there is no distortion of end plates. Take young's

modulus as 100 GPa, bulk modulus as 2000 MPa and poisson's ratio as 0.25. (5M+10M)

8. A cylinder of external diameter 300 mm and internal diameter 250 mm is shrunk over another

cylinder of external diameter of 250 mm and internal diameter 200 mm. The radial pressure at

the junction after shrinking ia 10 N/mm2. Find the final stresses set up across the section, when

the compound cylinder is subjected to an internal pressure of 90 N/mm2. (15M)

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Code No: R22031






~~~~~~~~~~~~~~~~~~~~~~

1. a) Draw stress-strain curve for steel. Explain its salient features.

b) A 30mm thick and 200mm wide steel plate tapers uniformly to 20mm thickness and 150 mm

width over a length of 2 m. Determine the increase in length when a pull of 20 kN is applied

Take young's modulus of elasticity as 210 GPa. (7M+8M)

2. Draw shear force and bending moment diagrams for the beam shown in Fig. 1 and indicate the

main values. (15M)

12 kN/m20 kN-m

4 m 2 m 1.5 m

AB C

D

Fig. 1

3. The tension flange of a girder of I-section is 200 mm x 40 mm, whereas the compression flange

is 150 mm x 20 mm. The web is 300 mm deep and 20 mm thick. If the girder is used as simply

supported beam of 10 m span, determine the load per unit run if the allowable stress is 100MPa

in compression and 40 MPa in tension. (15M)

4. Determine the maximum shear stress induced in a beam with the following cross-sections when

subjected a shear force of F. compare it with its mean stress.

a) Square cross section with the diagonal horizontal and the length of the diagonal is B.

b) Triangular cross section with its depth D and base W. (8M+7M)

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Code No: R22031

5. a) What are the assumptions made in the analysis of frames and trusses?

b) Determine the forces in the members CE, GE and GB of the frame shown in Fig. 2 using

method of sections. D and E are the mid points of AC and BC respectively. (6M+9M)

6. Determine the deflection at the points B and C of the beam shown in Fig. 3. The flexural

rigidity of the beam is 90,000 kN-m2. Use double integration method. (15M)

90 kN40 kN

1 m

1 m3 m 2 m

A

B C

D

Fig. 3

7. a) What are the assumptions made in the analysis of thin cylinders? Derive the expressions for

hoop and longitudinal stresses developed in them.

b) A cylindrical boiler drum has hemispherical ends. The cylindrical portion is 1.5 m long and

720 mm in diameter and 18 mm thick. It is filled with water at atmospheric pressure.

Determine the volume of additional water required to be filled in the drum to raise the

pressure in the drum to 12 MPa. Assume the hoop strain at the junction of cylinder and the

hemisphere to be the same for both. Take young's modulus of elasticity as 200 GPa, Bulk

modulus as 2100 MPa and poisson's ratio as 0.3. (6M+9M)

8. a) Derive Lame's equations.

b) Determine the thickness of metal necessary for a thick cylindrical shell of internal diameter

160 mm to withstand an internal pressure of 10 N/mm2. The maximum hoop stress in the

section is not to exceed 40 N/mm2. (8M+7M)

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Code No: R22031






~~~~~~~~~~~~~~~~~~~~~~

1. a) A bar of 3 m long and 15mm diameter, hangs vertically and has a collar attached at the lower

end. Determine the maximum stress induced when a weight of 100 kg falls through a height

of 20 mm on to the collar.

b) A steel bar of 15 mm diameter is subjected to an axial load of 15 kN. If the change in

diameter is found to be 0.0024 mm, determine the poisson's ratio, modulus of elasticity and

bulk modulus. Take rigidity modulus as 78 GPa. (6M+9M)

2. Draw shear force and bending moment diagrams for the overhanging beam shown in Fig. 1and

indicate the main values. (15M)

20 kN/m

10 kN

16 kN/m

3 m 2 m 2 m

AB

CD

Fig. 1

2.5 m

1 m

3. a) A 300 mm x 80 mm I-beam is to be used as a simply supported beam of 7 m span. The web

thickness is 10 mm and the flanges are 15 mm thickness. Determine the magnitude of

concentrated load that can be carried at a distance of 3 m from one support if the maximum

permissible stress is 90 MPa.

b) Compare the bending resistances of a beam with square cross section placed with two sides

horizontal to that with a diagonal horizontal for the same stress in each case. (10M+5M)

4. Determine the shear stress induced in a beam at its neutral axis with the following cross-

sections when subjected a shear force of F. compare it with its mean stress.

i) Hexagonal cross section with two parallel sides horizontal and the length of each side is B.

ii) Circular cross section of diameter D. (8M+7M)

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Code No: R22031

5. Determine the value of the force P which produces a force 200 kN in the member AB of the

cantilever frame shown in Fig. 2. Also determine the forces in the members GH and AG.(15M)

A BC

DEGH

3 m 6 m 6 m

4 m

Fig. 2

P

P

2P

P

P

6. Determine the deflection at the free end of the beam shown in Fig. 3 and the maximum

deflection between A and B. Assume young's modulus of elasticity as 200 GPa and I = 12 x 106

mm4. (15M)

A BCD

E

1 m 3 m 2 m 1 m

4 kN/m

6kN

Fig. 3

7. a) What are the stresses developed in a thin spherical shell and find the expressions for the

stresses and volumetric strain.

b) A thin spherical steel shell of 1.5 m diameter and uniform thickness is filled with water at a

pressure of 2.5 MPa. The relief valve attached to the shell is opened to allow the water to

escape until the pressure inside the shell drops to atmospheric pressure. If the volume of

water escaped is 4500 c.c., determine the thickness of the plates of the shell. Take young's

modulus of elasticity as 200 GPa, Bulk modulus as 2100 MPa and poisson's ratio as 0.3.

(5M+10M)

8. A steel tube of 200 mm external diameter is to be shrunk onto another steel tube of 60 mm

internal diameter. The diameter at the junction after shrinking is 120mm. The difference of

diameters at the junction is 0.09 mm before shrinking on. Calculate the radial pressure at the

junction and the hoop stresses developed in the two tubes after shrinking on. Take young's

modulus of elasticity as 200 GPa. (15M)

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Code No: R22043


ELECTRONIC CIRCUIT ANALYSIS (Com. to ECE, EIE)




~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the equations for the current gain, input impedance, voltage gain and output

impedance of an emitter follower operating at low frequencies in terms of common emitter

h-parameters

b) Using Miller’s theorem, prove that for a CE amplifier with resistive load the output

voltage is –gmRL (8M+7M)

2. a) A Common source FET amplifier has a load resistance of 500kΩ. The ac drain resistance of

the device is 100kΩ and the transconductance is 0.8mAV-1

. Calculate the voltage gain of

the amplifier.

b) Draw the block diagrams of four types of negative feedback amplifier circuits and explain

which amplifier can be used to get higher input impedance and lower output impedance with

appropriate derivation (8M+7M)

3. a) Draw the circuit diagram of Colpitt’s oscillator. Explain its disadvantages. How it is

overcome with Clapp oscillator.

b) Prove that in an RC-phase shift oscillator, the minimum hfe required is 29 to sustain the

frequency of oscillations (8M+7M)

4. a) For a cascaded CE-CC configuration, the h-parameters are given as hie=1kΩ, hre=10-4

,

hfe=50, hoe=10-4

A/V, hic=1kΩ, hrc=1, hfc= -51, hoc=10-4

A/V. Find the input and

output impedances of the cascaded configuration

b) Derive the expressions for overall voltage gain, current gain and power gain, when two

identical amplifier stages are cascaded (8M+7M)

5. a) Define fβ and fT and also derive the relation between them

b) Given the following transistor measurement made at Ic = 5 mA, Vce = 10V and at room

temperature: hfe = 100, hie = 600 ohm, Ai = 10 at 10MHz, Cc= 3 pF. Calculate fβ, fT, Ce,

rb’,e and rbb’. (8M+7M)

6. a) Derive the efficiency of the class-B power amplifier. Though class-B single ended power

amplifier efficiency is high, why it is not used in practical circuits? Explain in detail.

b) What are the disadvantages of using transformers in a push-pull amplifier? Explain a few

techniques that eliminates the use of input transformers (8M+7M)

7. a) Compare single and double tuned amplifiers. Draw the circuit of double tuned amplifier and

also explain how the frequency response of this amplifier is better than the single tuned

amplifier

b) What is importance of stagger tuning? Explain briefly about stagger tuned amplifiers.

(8M+7M)

8. a) Explain how overload protection is provided in series voltage regulator

b) Distinguish between series voltage regulator and shunt voltage regulator. (8M+7M)

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Code No: R22043






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the equation for voltage gain and input impedance of a common source JFET

amplifier with the help of its circuit diagram and its equivalent circuit.

b) Calculate Ai Ri, Av, Ro for the CC amplifier circuit with CE h-parameters given by hfe=50,

hie=1k, hoe = 50k also the resistance parameters given by RL=1k Ω,

RS= 100Ω, R1 = 100k Ω, R2 = 10kΩ, RE = 1kΩ (7M+8M)

2. a) Apply the method of feedback circuit analysis for a voltage series feedback amplifier and

explain all steps with appropriate diagrams

b) Prove that negative feedback in amplifiers reduces the distortion and noise with appropriate

equations (7M+8M)

3. a) Derive the equation for frequency of oscillations of a FET RC-phase shift Oscillator and also

derive condition for sustained oscillations.

b) Prove that the gain of Wien bridge oscillator using BJT amplifier must be at least 3 for the

oscillations to occur. (7M+8M)

4. a) Show that the input impedance and overall voltage gain of a Darlington pair is much larger

compared to an individual CE amplifier with same transistor.

b) Derive the expression for current gain of a two stage RC coupled CE amplifiers (7M+8M)

5. a) What is Giacelletto model of a transistor? Discuss about various parameters in the model.

b) Derive an expression for voltage gain of common source amplifier at high frequencies.

(7M+8M)

6. a) Explain how the power amplifiers are classified based on class of operation and also compare

them

b) A single transistor is operating as an ideal class B amplifier with a 1-K load. A dc meter in

the collector circuit reads 10mA. How much signal power is delivered to the load?

(7M+8M)

7. a) Explain the operation of a single tuned amplifier circuit and its frequency Response.

b) Derive the efficiency of class C tuned amplifier and explain its operation (7M+8M)

8. a) Distinguish between overload and over current protection in regulators?

b) Explain the operation of a Zener diode as a Voltage Regulator (7M+8M)

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Code No: R22043






~~~~~~~~~~~~~~~~~~~~~~~~

1. a) Derive the equation for the gain of a common emitter amplifier with emitter resistance and

also explain the effect of emitter resistance on the gain

b) What is small signal model of a FET. Derive the relationship between small signal

parameters of a FET. (7M+8M)

2. a) An Amplifier with negative feedback gives an output of 12.5V with an input of 1.5V. When

feedback is removed, it requires 0.25V input for the same output. Find i) Value of voltage

gain without feedback ii) Value of β, if the input and output are in phase and β is real.

b) Explain the procedure to obtain the basic amplifier configuration without feedback but

taking the loading of the feedback network into account (7M+8M)

3. a) Derive the expression for frequency of oscillation of BJT phase-shift oscillator and explain

its operation with neat circuit diagram

b) A crystal oscillator has the following parameters: L=0.33H, C=0.065pF, C=1.0pF and

R=5.5 kΩ. i) Find the series resonant frequency. ii) Find the Q of the crystal. (7M+8M)

4. a) What is frequency response of an amplifier? Draw the equivalent circuits of RC coupled

amplifier at low and high frequencies and derive the expression for voltage gain.

b) Two FET based amplifiers with gains of 30 dB are cascaded together. Find the overall gain.

Also find bandwidth of the overall circuit, if individual lower and higher 3 dB frequencies

are 20 Hz and 20 kHz respectively. (7M+8M)

5. a) Draw the high frequency hybrid π model of a BJT and explain the each parameter of the

Model with appropriate equation.

b) Derive the equations for transconductance and input conductance of CE amplifier using

high frequency model. (7M+8M)

6. a) Derive the expression for Maximum efficiency and working of transformer coupled Class A

Amplifier

b) Define collector circuit efficiency of a power amplifier and explain how total distortion can

be reduced in a power amplifier through push-pull configuration. (7M+8M)

7. a) Show that for an “n” stage synchronously tuned amplifier, maximum. bandwidth is obtained

when the single stage gain is 4.34 dB.

b)Explain how the stagger-tuned design is superior to synchronously tuned design in the design

of a multistage amplifier? (7M+8M)

8. a) Describe the operation of a BJT series regulator and derive the equations for load and line

regulations

b) List and explain current limiting techniques used in voltage regulators (7M+8M)

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1. a) An Emitter follower circuit has the following parameters RL=1kΩ, RS= 50Ω, hfe=50,

hie = 1kΩ, hoe = 50kΩ, R1 = 100kΩ, R2 = 10kΩ, RE = 10kΩ. Calculate Ri, Ro,Av, and Ai for

the above circuit.

b) Derive an expression for the voltage gain of common source amplifier by using low

frequency equivalent circuit. (7M+8M)

2. a) An amplifier has a mid band gain of 125 and bandwidth of 250 kHz. If 4% negative

feedback is introduced and the new bandwidth and gain.

b) Derive the equations for voltage gain, input impedance and output impedance of a CE

amplifier with current-shunt negative feedback. (7M+8M)

3. a) Find the capacitance C and hfe for the transistor Phase-Shift oscillator to provide a

resonating frequency of 10kHZ. Assume R1=25kΩ, R2=60 kΩ, Rc=40kΩ, R=7.1kΩ and

hie=1.8kΩ.

b) Explain barkhausen criterion for sustained oscillations and also explain how the criterion

is satisfied in a BJT RC- Phase-Shift oscillator (7M+8M)

4. a) For a Darlington pair the overall current gain and input impedance with an emitter resistance

are given as 1130Ω and 1.2 MΩ respectively. Calculate the value of emitter resistance RE.

b) Three identical stages of amplifiers cascaded with lower and upper cut off frequencies given

by 300Hz and 5kHz respectively, compute the overall lower and higher cut off frequencies

with appropriate equations. (7M+8M)

5. a) The following low frequency parameters are known for a given transistor at Ic = 10 mA,

VCE =5V, hie = 500, hoe = 10−5A/V, hfe = 100, hre = 10−4. At the same operating point

fT = 50 MHz, and Cc = 3 PF, compute the values of all the hybrid-π parameters.

b) Draw the circuit of single stage RC coupled BJT amplifier. Discuss the effect of an

emitter bypass capacitor on low frequency response. (7M+8M)

6. a) Differentiate between push-pull and complementary-symmetry configurations of a class B

power amplifier.

b) Explain the reasons for crossover distortion in class-B power amplifiers and suggest a

suitable circuit for its minimization. (7M+8M)

7. a) Explain the working of Single Tuned Amplifier with circuit diagram.

b) Explain the significance of various levels of coupling of transformer used in double tuned

amplifiers with necessary diagrams. (7M+8M)

8. a) Explain the operation of BJT shunt voltage Regulator with the help of a neat circuit Diagram

b)Explain short circuit and overload protections in a voltage regulator through relevant circuits.

(7M+8M)

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Code No: R22051


SOFTWARE ENGINEERING (Computer Science and Engineering)




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1. a) Define software. List and explain about the elements of a software process.

b) How does a framework activity change as the nature of the project changes?

2. a) Which model couples the iterative nature of prototyping with the controlled and systematic

aspect of the waterfall model? Explain its key features.

b) Give the classification of software system requirements.

3. a) What checks are done during requirements validation? Explain various techniques used for

requirements validation.

b) Which model shows how data flows through a sequence of processing steps? Give the data

flow diagram of order processing.

4. a) Briefly describe each of the four elements of the design model.

b) What is an architectural pattern? How can the architectural style be assessed?

5. a) Briefly explain the steps in user interface design evaluation cycle.

b) Using UML graphical notation for object classes, design the following object classes

identifying attributes and operations.

- A Bank account

- An ATM

6. a) What are the differences between alpha testing, beta testing, stress testing and smoke

testing?

b) What is a good test? Give the characteristics of testability.

7. a) How will you measure software quality? Explain.

b) Briefly explain about RMMM plan. List various components of risk information sheet.

8. a) Why is review important for assessing quality? List the review metrics that are to be

collected for each review that is conducted.

b) Can a program be correct and still not be reliable? Explain.

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SOFTWARE ENGINEERING

(Computer Science and Engineering)




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1. a) What is software engineering? Briefly explain five generic process frame work activities.

b) What formal techniques are available for assessing the software process? Explain them.

2. a) Briefly explain about various phases of Unified process.

b) What are non functional requirements? List various types in it. Briefly explain about the

metrics used for specifying non-functional requirements.

3. a) What is meant by feasibility study? Give the general process model of the requirements

elicitation and analysis process.

b) Which model describes how a system responds to internal or external events? Give the state

machine model of a simple microwave oven.

4. a) Why is quality so important in software design? Explain with examples.

b) Is it necessary to assess an architectural style that is adopted for design? Justify.

5. a) What is the goal of user interface design? What do we need to know about the environment

as we begin UI design?

b) Using UML graphical notation for object classes, design the following object classes

identifying attributes and operations.

- A Telephone

- An ATM

6. a) What errors are commonly found during unit testing and top-down integration?

b) What is a flow graph? How can cyclomatic complexity be calculated?

7. a) What are direct and indirect measures? Why are such measures common in software

metrics?

b) What is risk mitigation? What can be done to mitigate a risk?

8. a) What is a formal technical review? Give a set of guidelines for formal technical reviews.

b) Is it possible to assess the quality of software if the customer keeps changing? Explain.

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1. a) What is a process model? How do process models differ from one another?

b) Compare and contrast personal and team process models.

2. a) What is the oldest paradigm for software engineering? Why does the waterfall model

sometimes fail?

b) What are system requirements? What notations are used for requirements specifications?

3. a) Briefly explain the requirements engineering process.

b) Based on your experience with a bank ATM, draw a data-flow diagram modeling the data

processing involved when a customer withdraws cash from the machine.

4. a) Discuss the importance of data abstraction in the software design process.

b) List the differences between data flow architecture and data centered architecture.

5. a) Under what circumstances might you develop a design where objects execute concurrently?

b) How do we learn what the user wants from the User Interface?

6. a) What guidelines lead to a successful software testing strategy?

b) What is a test case? How test cases can be derived?

7. a) Describe the differences between project metrics and process metrics.

b) What is risk projection and how the consequences of risk be assessed?

8. a) Explain the differences between an error and a defect? Why can’t we wait until testing to

find and correct all software errors?

b) Why would a software development team want to make use of an independent software

quality assurance group?

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1. a) Why is it important to understand the customer’s problem before creating a software

solution?

b) What is a process? What are the generic framework activities that are present in every

software process?

2. a) Briefly explain about incremental process models.

b) What is Software requirements document? Give the structure of it.

3. a) Explain about the requirements of elicitation and analysis in detail.

b) Develop an object model, including a class hierarchy diagram and an aggregation diagram

showing the principal components of a personal computer system and its system software.

4. a) How are the concepts of coupling and cohesion related to software module size?

b) What is an architectural style? Briefly explain about layered architectures with example.

5. a) Using examples, explain the difference between an object and an object class.

b) How do we determine the format and aesthetics of content displayed as part of the User

Interface?

6. a) What is the overall strategy for software testing? When to stop testing?

b) What is a graph matrix? Explain its usage in testing. How can equivalence classes be defined

for testing?

7. a) What is the difference between metrics and measurements? Give metrics for maintenance.

b) What is a risk? What types of risks are likely to encounter as software is built?

8. a) What are the different ways in which quality can be viewed? Write short notes on McCall’s

software quality factors.

b) Besides counting errors and defects, are there any other countable characteristics of software

that imply quality? What are they and can they be measured directly?

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