Electro Technical Officer(ETO) Exam Questions

Examination of Electrical Technical Officer

(Marine Electrotechnology and SSEP)

1. Explain three methods of overcurrent protection for electrical circuits. Explain with the aid of the diagram, the meaning of the term inverse current time characteristic?

2. State the application of the synchronous motors. Discuss how a synchronous motor can function as a synchronous capacitor. Compare synchronous motors with induction motors drives?

3. What is Zener diode and how does it regulate the voltage? What happens to the series current, load current, and Zener current, when the d.c. the input voltage of a Zener regulator increase? Draw a neat diagram of the Zener regulator and explain it? 

4. With Reference to 3-phase transformers

a. Discuss the essential and desirable conditions to be fulfilling for operating two three-phase transformers in parallel.

b. What are the advantages of transformers bank of three 1-phase transformers over a unit three-phase transformers of the same KVA rating?

5. Sketch and describe the main engine shaft driven generator arrangement with an electronic system for frequency correction.

6. With respect to alternator onboard:

a. Briefly explain true power, Apparent power, and power factor?

b. The alternator is rated for 750 KVA at 0.85 PF, what is the maximum load (KW) that can be put on it? Would you be overloading the alternator if the KW reading were now 620 KW and the PF 0.80?

7. Write a short note on “electric shock”?

8. How will you fight a fire in a purifier room? How will you at least restrict the fire if you are the first person to sight the fire in the purifier room?

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Communication System Multiple Choice Questions

 Electronics and Communication Multiple Choice Questions

1. In PCM if the transmission path is very long?

a. repeater stations are used

b. pulse width may be increased

c. pulse amplitude is increased

d. pulse spacing is reduced

2. Frequency shift keying is used mostly in?

a. radio transmission

b. telegraphy

c. telephony

d. none of these

3. Leak type bias is used in a plate modulated class C amplifier to?

a. increase the bandwidth

b. prevent excessive grid current

c. prevent tuned circuit damping

d. prevent overmodulation

4. The frequency of normal sound wave determines its?

a. quantity

b. echo

c. loudness

d. pitch

5. Which of the following is most likely to be found in an SSB transistor?

a. Class A, RF output amplifier

b. Class B, RF amplifier

c. tuned modulator

d. Class C, audio amplifier

6. A longwave AM Broadcast transmitter needs?

a. very small carrier power

b. very large carrier power

c. small carrier power

d. large carrier power

7. The term noise temperature is used for?

a. white noise source only

b. thermal noise source only

c. non-thermal noise source only

d. all of the above

8. The thermal noise is due to random?

a. motion of atoms and molecules

b. motion of free electrons

c. vibrations of atom about their mean position, inside the conducting medium

d. none of these

9. At high frequencies, which of the following types of noise become most important?

a. flicker noise

b. short noise

c. thermal noise

d. transit time noise

10. Which of the following is not uniformly distributed over all frequencies?

a. white noise

b. flicker noise

c. short noise

d.  thermal noise

Answers:

1. a

2. b

3. b

4. d

5. b

6. b

7. d

8. b

9. d

10. b

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Control System Multiple Choice Questions

 Electronics and communication Multiple Choice Questions

1. Poles are the complex frequencies of a transfer function where the response becomes?

a. infinite

b. zero

c. oscillatory

d. decaying

2. Zeros are the complex frequencies of a transfer function where the response becomes?

a. infinite

b. zero

c. oscillatory

d. decaying

3. Which of the following is an open loop system?

a. ward Leonard control

b. Amplidyne

c. Armature controlled d.c. motor

d. Field controlled d.c. motor

4. A driver maintains the speed of a car at 50 Km per hour. Here the feedback element is?

a. steering wheel

b. needle of the speedometer

c. eyes

d. all of these

5. Transient response of a system is basically because of?

a. coupling

b. forces

c. friction

d. stored energy

6. In a critically damped system, the damping factor of the system is?

a. zero

b. unity

c. less than unity

d. greater than unity

7. With feedback, the transient response of the system as compared to that without feedback?

a. decays slowly

b. decays more quickly

c. rises at a faster rate

d. remain unaltered

8. By increasing the gain k of the system, the steady state error of the system?

a. decreases

b. increases

c. remain unchanged

d. may increase or decreases

9. Integral error compensation is also called?

a. proportional minus integral compensation

b. proportional plus integral compensation

 c. proportional plus derivative compensation

d. proportional minus derivative compensation

10. For 2% tolerance band, the settling time the second order linear system is? Where t is the time constant.

a. t/2

b. t

c. 2t

d.  4t

Answers:

1. a

2. b

3. d

4. b

5. d

6. b

7. b

8. a

9. b

10. d

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Digital Electronics Circuits Multiple Choice Questions

Electronics and Communication Multiple Choice Questions

1. Scratch-pad memory is a?

a. first-in-first-out memory

b. last-in first-out memory

c. local permanent memory

d. local temporary memory

2. In case of bipolar or static MOS memories, the access time is about?

a. 20 to 400 ns

b. 20 to 400 micro sec

c. 20 to 400 ms

d. 20 to 400 s

3. Access in the magnetic drum is?

a. completely random

b. sequential and cyclic

c. cyclic sequential

d. partly random and partly cyclic sequential

4. Dynamic memory cells are constructed using?

a. FETs

b. MOSFETs

c. Transistor

d. Flip-flops

5. ROM consists of?

a. a decoder followed by an encoder

b. an encoder followed by a decoder

c. a multiplexer followed by a decoder

d. none of these

6. Semiconductor ROMs are sometimes preferred to semiconductor RAMs because?

a. ROMs are cheaper than RAMs

b. ROMs are faster

c. ROMs do not require the power supply for their operation

d. a program stored in ROMs cannot be altered

7. Which of the following is a permanent memory?

a. RAM

b. ROM

c. both RAM and ROM

d. None of the above

8. The storage device used to compensate the differences in the ratio of flows of data is known as?

a. auxiliary storage

b. buffer

c. main storage

d. None of the above

9. Desirable characteristics of a memory unit are?

a. compact

b. speed

c. durability

d. all of the above

10. Parallel adders are?

a. Combinational logic circuits

b. sequential logic circuit

c. both of the above

d.  none of the above

Answers:

1. d

2. a

3. d

4. b

5. a

6. d

7. b

8. b

9. d

10. a

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Power Electronics Multiple Choice Questions

Electronics and Communication Multiple Choice Questions

1. A step up chopper is required to deliver a load voltage of 660V from a DC source of 220V. Let the non-conduction time of thyristor be 100 micros required the requited pulse width, ton:

a. 150 micro sec

b. 200 micro sec

c. 330 micro sec

d. 240 micro sec

2. The thyristor can be turned on by applying?

a. a positive signal to gate

b. a negative signal to gate

c. holding current to the gate

d. none of the above

3. When two SCRs are connected in parallel configuration?

a. the SCR with lower dynamic resistance will carry lesser value of current

b. the SCR with lower dynamic resistance will carry higher value of current

c. both the SCR with carry equal values of current even if their dynamic resistance are different

d. none of the above

4. A class-C chopper (DC to DC converter) is also known as?

a. one-quadrant regulator

b. two-quadrant chopper

c. steady state chopper

d. all of the above

5. The flyback converter topology in a DC to DC switched mode power supply?

a. should be restricted to low power application

b. can be used for high power application

c. would be selected depending upon the DC load of the equipment in question

d. can be selected without considerations of power requirement of the equipment in questions.

6. A UPS is an example of?

a. a DC SMPS

b. an AC SMPS

c. a DC to DC converter

d. a voltage regulation device

7. An n-channel enhancement MOSFET?

a. has a physical channel

b. has no physical channel

c. is similar in construction to a p channel depletion MOSFET

d. none of these

8. The enhancement MOSFETs responds to?

a. positive and negative gate voltages

b. positive gate voltage only

c. negative voltage only

d. none of above is true

9. A DC chopper (DC to DC converter) is turned on for 30 micro sec and turned off for 10 micro sec. What is its duty cycle?

a. 0.62

b. 0.92

c. 0.75

d. 0.85

10. In a three-phase bridge inverter?

a. firing of SCRs can be done for a period of 120 degree only

b. firing of SCRs can be done for a period of 180 degree only

c. firing of SCRs can be done for a period of 120 degree and 180 degree periods

d.  none of the above

Answers:

1.  b

2. a

3. b

4. b

5. a

6. b

7. b

8. b

9. c

10. c

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Electronic Measurement and Instrumentation Multiple Choice Questions

Electronic and Communication Multiple Choice Questions

1. The accuracy of the digital voltmeter is specified as:

a. percentage of the actual reading

b. percentage of the full-scale reading

c. number of least significant digits

d. all of the above

2. An FET VM employs FETs in?

a. cascade mode

b. cascode mode

c. differential mode

d. common mode

3. A DVM measure?

a. peak value

b. rms value

c. peak to peak value

d. average value

4. Resolution of DVM with 4 digit display is?

a. 1/4

b. 1/1000

c. 1/1000

d. 1%

5. The best method of measuring capacitance is the?

a. CRO method

b. transistor-Voltmeter method

c. voltmeter-ammeter method

d. a.c bridge method

6. Transistor voltmeter is a?

a. dynamometer type instrument

b. moving iron instrument

c. moving coil instrument

d. none of these

7. Parallel connection Q meter is used for measuring?

a. Low impedance component

b. High impedance component

c. a and b both

d. none of these

8. Transistor voltmeter is a highly sensitive instrument and can be used for measurement of?

a. energy

b. power

c. voltage and current

d. d.c. voltage only

9. Transistor voltmeter?

a. cannot measure a.c. voltage

b. cannot be designed to measure resistance as well as voltage

c. cannot measure high-frequency voltage

d. can measure a.c. voltage

10. The maximum input signal frequency that can be used with a CRO is limited by?

a. input probe capacitance

b. the vertical amplifier

c. the frequency of the sync signal

d.  the horizontal amplifier

Answers:

1.  d

2. c

3. d

4. c

5. d

6. c

7. b

8. c

9. d

10. b

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Electromagnetic Theory Multiple Choice Questions

Electronics and communication Multiple Choice Questions

1. The electric field intensity magnitude at a point (1,2,3) m, in Cartesian coordinates due to a charge(1/9) nC located at the origin is equal

a. 3.3 V/m

b. 0.33 V/m

c. 0.033 V/m

d. zero

2. The divergence theorem applies to?

a. static fields only

b. time-varying fields only

c. both static as well as time-varying fields

d. magnetic fields only

3. For a plane electromagnetic wave traveling in a linear, isotropic, homogeneous stationary medium?

a. E and H lie in the same plane

b. E * H = 0

c. E and H are mutually perpendicular

d. None of these

4. An electromagnetic wave propagates from a dielectric medium to the interface with free space. If the angle incidence is the critical angle of 30 degrees, the relative permittivity of the dielectric medium is?

a. 8

b. 4.5

c. 6.8

d. 4

5. When an electromagnetic wave traveling in one medium strike upon a second medium having a different conductivity the wave will be?

a. neither transmitted and partially reflected

b. totally reflected

c. partially transmitted and partially reflected

d. totally transmitted

6. In the perfect conductor, the incident and the reflected waves combine to produce?

a. linearly polarized

b. circularly polarized

c. elliptically polarized

d. horizontal polarized

7. The polarization of dielectric materials results in?

a. absorption of electrons

b. the release of high-velocity protons

c. creation of electric dipoles

d. production of eddy currents

8. The absorption of radio waves by the atmosphere depends on?

a. the polarization of atmosphere

b. the polarization of the waves

c. their frequency

d. their distance from the emitter

9. As an electromagnetic wave travels in free space the only one of the following can happen to them?

a. reflection

b. absorption

c. attenuation

d. refraction

10. When a current carrying conductor is brought into the magnetic field the force that moves the conductor depends upon which of the following?

a. The value of current

b. The weight of conductor

c. The direction of the conductor

d.  None of these

Answers:

1.  b

2. c

3. c

4. d

5. c

6. c

7. c

8. c

9. c

10. a

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Network Theory Multiple Choice Questions

Electronics and Communication Multiple Choice Questions

1. Zero of a network is the critical frequency at which network function becomes___

a. zero

b. unity

c. infinite

d. sinusoidal

2. Poles of E z(s) are:

a. always simple

b. always in multiple form

c. always imaginary

d. either simple or of higher multiplicity

3. An impedance function whose real part vanishes at some real frequency is called?

a. minimum impedance function

b. minimum reactance function

c. minimum susceptance function

d. minimum resistance function

4. A minimum reactance function is one which has?

a. no zero at origin

b. no poles at origin

c. no zero on imaginary axis

d. no poles on the imaginary axis

5. In an impedance function, a pole at infinity is realized by using?

a. a capacitance In series

b. an inductance in series

c. an inductance in parallel with the driving point terminal

d. none of these

6. The response of a network is decided by the location of?

a. it's zero

b. it's poles

c. both zero and poles

d. neither zeros nor poles

7. As the poles of network shift away from the axis, the response?

a. remains constant

b. becomes less oscillating

c. becomes more oscillating

d. none of these

8. Pole of a network is a critical frequency at which network function?

a. becomes zero

b. becomes unity

c. becomes infinite

d. becomes very large

9. An inductor has self-resistance of 5 ohm and inductive reactance of 250 ohms at the operating frequency. The quality factor of the inductor is?

a. 1250

b. 50

c. 250

d. 5

10. The Q factor of a series LCR circuit increases if?

a. R increases

b. R decreases

c. applied voltage increases

d.  current decreases

Answers:

1. a

2. d

3. d

4. d

5. b

6. c

7. b

8. c

9. b

10. b

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