# Electronics Engineering Mastery Test 13: ECE Pre-Board

(Last Updated On: April 4, 2021) This is 100 items set of Practice Examination 13 in Electronics Engineering composed of previous and/or potential Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 4 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

#### Start the Test Yourself Exam 13

Choose the letter of the best answer in each questions.

1) A four-element solid-state device that combines the characteristics of both diodes and transistors.

a) Tunnel diode

b) Silicon controlled rectifier

c) Varactor

d) Zener diode

Solution:

2) What type of radar target bearing is referenced to your ship or aircraft?

a) True bearing

b) Magnetic bearing

c) Direct bearing

d) Relative bearing

Solution:

3) Which part of the computer performs mathematical operation?

a) ALU

b) CPU

c) Flip-flop

d) Assembly language

Solution:

4) The first mass-produced computer built by Eckert and Maunchy Computer Company in Philadelphia USA in 1950.

a) IBM – 701

b) CRAY-1

c) UNIVAC

d) ENIAC

Solution:

5) It is a sequence of operation in a digital computation.

a) Flow chart

b) Truth table

c) Algorithm

d) FORTRAN

Solution:

6) What is the central processor of the computer which is sometimes referred to as the heart of a computer system?

a) CPU

b) SOFTWARE

c) HARDWARE

d) ALU

Solution:

7) What is the process of designing more than 100 gates on a single chip?

a) LSI

b) SSI

c) MSI

d) VLSI

Solution:

8) _____ refers to a function of a decade counter digital IC.

a) Producing one output pulse for every 10 input pulses

c) Producing 10 output pulses for every 1 input pulse

d) Decoding a decimal number for display on seven-segment

Solution:

9) A series of predefined actions or operations performed on a collection of facts.

a) DATA PROCESSING

b) HASHING

c) FLOWCHARTING

d) ALGORITHM

Solution:

10) The physical machinery of a computer system.

a) Hardware

b) Tupperware

c) Software

d) Coldware

Solution:

11) Which of the following is not used in hexadecimal digital symbols?

a) A

b) C

c) H

d) F

Solution:

12) ___ refers to circuit with 10 to 100 integrated circuits.

a) IC

b) Monolithic

c) MSI

d) SSI

Solution:

13) The decimal 36 020 is equivalent to hexadecimal ___.

a) 8CB4

b) 8SBC

c) 8BC8

d) 884C

Solution:

14) What is the name of an electrode found in a pentode but not in a tetrode?

a) Control grid

b) Screen grid

c) Signal grid

d) Suppressor grid

Solution:

15) How do you call an eight element vacuum tube?

a) Pentode

b) Hexode

c) Octode

d) Septode

Solution:

16) What is a gain of a vacuum tube having the following parameters: amplification factor is 80, external plate-load resistance of 30 000 ohms and the tubes internal plate resistance is 10 000
ohms?

a) 60

b) 20

c) 30

d) 40

Solution:

17) What is the signal that provides color information in a colored TV?

a) composite

b) NTSC color bust

c) Chrominance

d) PAL SECAM

Solution:

18) An instrument used to measure one location in terms of coordinates.

a) Global Positioning System

b) Hydrometer

c) Altimeter

d) Increductometer

Solution:

19) ___ are individual points in graphic display.

a) Row

b) Pixel

c) Resolution

d) Column

Solution:

20) What is the reference cycle time in radar, when the signal is transmitted back to receiver?

a) 10.1 microsec

b) 100.0 microsec

c) 12.4 microsec

d) 24.8 microsec

Solution:

21) What does SI magnetic flux refer?

a) Weber

b) Flux

c) Maxwell

d) Lines

Solution:

22) ___ is the relative permeability of paramagnetic substances.

a) much lesser than 1

b) a little greater than 1

c) Equal to 1

d) Much greater than 1

Solution:

23) The time lag of the magnetic flux in a magnetic material behind the magnetizing force producing it caused by the molecular friction of the molecules trying to allow themselves with the
magnetic force applied to the material.

a) Hysteresis loop

b) Magnetic loss

c) Hysteresis

d) Hysteresis loss

Solution:

24) What is the magnetic equivalent of electrical resistance?

a) Reluctance

b) Magnetomotive force

c) Flux

d) Magnetic field

Solution:

25) An alloy that changes directly from solid to liquid with no plastic or semi-liquid state.

a) Amalgam

b) Nickel-bronze

c) Mercury

d) Eutectic alloy

Solution:

26) The current of an electronic circuit is analogous to ___ parameter of a magnetic circuit.

a) flux density

b) reluctivity

c) mmf

d) flux

Solution:

27) Term used in electronic measuring device when a material increases resistance due to heat produced by current flowing through them.

a) Positive resistance coefficient

b) Negative resistance coefficient

c) Positive temperature coefficient

d) Negative temperature coefficient

Solution:

28) Find which type of network provides the greatest harmonic suppression.

a) Pi-network

b) Pi-L network

c) Inverse Pi-network

d) L-network

Solution:

29) The maximum voltage that can be applied to a capacitor without the capacitor breaking down or shorting.

a) Capacitor voltage

b) Working voltage

c) Effective voltage

d) Maximum voltage

Solution:

30) Which of the following allows more current if applied to the same voltage?

a) 0.002 Siemen

b) 2.5 ohms

c) 25 ohms

d) 0.004 Siemen

Solution:

31) Where does practically all of the RF current flow in a conductor?

a) Along the surface

b) In the center of the conductor

c) In the electromagnetic field in the conductor center

d) In the magnetic field around the conductor

Solution:

32) How are networks able to transform one impedance to anther?

a) Resistance in the networks substitute for resistances in the load.

b) The matching network can cancel the reactive part of an impedance and change the value of the resistive part of an impedance.

c) The matching network introduces negative resistance to cancel the resistive part of impedance.

d) The matching network introduces transconductance to cancel the reactive part of an impedance.

Solution:

33) Who discovered the most important electrical effects, which is the magnetic effect?

a) Hans Christian Oersted

b) Sir Charles Wheatstone

c) Georg Ohm

d) James Clerk Maxwell

Solution:

34) Which of the following magnetic materials which can be easily magnetized in both direction?

a) Soft magnetic materials

b) Hard magnetic materials

c) High hysteresis loss materials

d) Low hysteresis loss materials

Solution:

35) Materials that have very high permeabilities (hundred and even thousand times that of free space).

a) Paramagnetic

b) Non-magnetic

c) Ferromagnetic

d) Diamagnetic

Solution:

36) The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called.

a) leftover magnetism

b) hysteresis

c) residual magnetism

d) coercivity

Solution:

37) The K shell or the first has how many permissible numbers of orbiting electrons?

a) 1

b) 2

c) 3

d) 4

Solution:

38) Flux density is measured in

a) tesla

b) weber

c) ampere=turn

d) Maxwell

Solution:

39) One oersted (Oe) is equivalent to ___ Gb/cm.

a) 1

b) 10

c) 100

d) 1000

Solution:

40) A magnetic flux of 2.5 x 10-4 Wb through an area of 5 x 10-4 square meters results in

a) 5 Wb of flux

b) 0.5 Tesla of flux density

c) 5 x 10-5 Wb of flux

d) 5000 Tesla of flux density

Solution:

41) If a 20 V potential is applied across a relay coil with 50 turns having 1 Ω of resistance, the total magnetomotive producing magnetic flux in the circuit is

a) 10 Wb

b) 50 T

c) 1000 A.t/m

d) 1000 A.t

Solution:

42) What is the reluctance of a magnetic path having a length of 2 x 10-3 m and cross-sectional area of 2.5 x 10-3 m2. The relative permeability is 100.

a) 6366 A.t/Wb

b) 6000 A.t/Wb

c) 8 x 10-3 A.t/Wb

d) 0.8 A.t/ Wb

Solution:

43) How many turns are needed to produce a magnetomotive across a solenoid of 100 turns having a resistance of 2 Ω. Calculate the number of ampere-turns?

a) 100

b) 50

c) 300

d) 600

Solution:

44) Series resonance occurs when

a) XL = XC

b) XL = R

c) Z = R

d) Both a and c

Solution:

45) At what frequency will an inductor of 5 mH have the same reactance as a capacitor of 0.1 µF?

a) 7.12 kHz

b) 4.12 Hz

c) 7.12 MHz

d) 7.12 GHz

Solution:

46) In a series RLC circuit

a) the current lags VL by 90°

b) the current leads VL by 90°

c) XL leads XC by 90°

d) Z = jXL at resonance

Solution:

47) Which of the following conditions is not true for a series RLC circuit at resonance?

a) Z = jXL

b) XL = XC

c) The power factor is one

d) The magnitude Z is √(R2 + (XL – XC)2)

Solution:

48) If three 9 mH inductors are connected in parallel without mutual inductance, then the total inductance is

a) 3 mH

b) 9 mH

c) 27 mH

d) 18 mH

Solution:

49) If resonant frequency is 10 kHz and quality factor is 50, then

a) bandwidth is 200 Hz

b) XL = is 50, 000 ohms

c) R is 50 ohms

d) XC = is 50, 000 ohms

Solution:

50) At what frequency will the current in a series RLC circuit reach its maximum value for an applied voltage of 15 with R = 500 Ω, L = 100 µH and C = 0.001 µF?

a) 503 kHz

b) 403 kHz

c) 603 kHz

d) 303 kHz

Solution:

51) A series RLC circuit consists of a 10Ω resistor in series with L = 10µH, and C = 100 µF. Determine a new value of L for which the resonant frequency is one-half the original value.

a) 40µH

b) 10 mH

c) 40 pH

d) 40 nH

Solution:

52) A 0.09 microfarad capacitor is charged to 220 Volts. How long in milliseconds will it discharged to a level of 110 V if the discharged resistor has a resistance of 20, 000 ohms?

a) 1.5

b) 2.5

c) 1.25

d) 0.5

Solution:

53) A trigger circuit consisting of a capacitor of 0.01 µF is connected in series with a resistor. If the circuit requires 100 Vdc to operate, determine the value of the resistor when the constant is 0.009s.

a) 900 Ω

b) 900 kΩ

c) 900 MΩ

d) 900 GΩ

Solution:

54) What is the peak factor for alternating current or voltage varying sinusoidally?

a) 1.4142

b) 0.707

c) 0.636

d) 1.11

Solution:

55) What is the complex impedance of a circuit with an absolute resistance of 300 Ω?

a) 0 + j 300 Ω

b) 300 + j 90 Ω

c) 0 – j 300 Ω

d) 300 + j 0 Ω

Solution:

56) Type of MOSFET that can be independently controlled by two separate signals.

a) JFET

b) Dual-gate MOSFET

c) Induced channel MOSFET

d) IGFET

Solution:

57) It exhibits a negative temperature coefficient.

a) conductor

b) semi-conductor

c) super conductor

d) ceramic

Solution:

58) In order to have the best efficiency and stability, where on the load line should a solid-state power amplifier be operated?

a) Just below the saturation point

b) At 1.414 times the saturation point

c) Just above the saturation point

d) At the saturation point

Solution:

59) Find from the following statements, description of a defective diode.

a) Diode resistance is either very low or very high on either direction.

b) Very low current

c) High voltage

d) High current

Solution:

60) Solve the collector current if base current is 200 mA and the current gain is 20.

a) 10 A

b) 4 A

c) 1 A

d) 40 A

Solution:

61) Solve for the base current if collector current is 600 mA and the current gain is 20.

a) 30 mA

b) 3 mA

c) 12 mA

d) 1.2 mA

Solution:

62) A good material conductor should have ___ valence electrons.

a) 21

b) 1

c) 3.5

d) 10

Solution:

63) A ___ is a junction field-effect transistor with Schottky barrier instead of a normal semiconductor junction.

a) biFET

b) MOSFET

c) MESFET

d) JUGFET

Solution:

64) In the operation of a dry cells we normally refer to the supply of current to load resistance where its current neutralize the separated charges at the electrons.

a) Aligning the cells

b) Charging the cells

c) Discharging the cells

d) Polarizing the cells

Solution:

65) Find the output of a four (4) lead acid cells.

a) 3.2 V

b) 8.4 V

c) 5.8 V

d) 1.6 V

Solution:

66) Find unloaded output of a power supply having a transformer regulation of 11.10% and 900 V load output.

a) 99.99 V

b) 90 V

c) 999.9 V

d) 900 V

Solution:

67) Determine how long a battery will last whose rating is 100Ah; 24 volts and will run a 300 watts electronic equipment and a 50 watts light.

a) 6.85 hours

b) 50.05 hours

c) 12.00 hours

d) 26.65 hours

Solution:

68) Which of the following statements is not true?

a) Edison cell is storage type.

b) The Nicd cell is primary type

c) Output of solar cell is normally 0.5 V.

d) Primary cells can be charged.

Solution:

69) Type of cell used mostly for emergency equipment. It is light, small, and has a large capacity of power for its size.

a) Ni-cd cell

c) Silver-zinc cell

d) Mercury cell

Solution:

70) Find the frequency in kilocycle per second in the armature of a 10 pole, 1, 200 rpm generator.

a) 100.0

b) 1000.0

c) 10.00

d) 0.100

Solution:

71) How many silver zinc cells in series are needed for a 9V battery?

a) 9

b) 6

c) 3

d) 7

Solution:

72) How much is the secondary voltage of a power transformer whose parameters are as follows, primary voltage is 240 V, 140 turns in the primary and 7 turns in the secondary.

a) 12 V

b) 24 V

c) 6 V

d) 36 V

Solution:

73) How many nickel-cadmium cells are needed in series for a 10 V battery?

a) 8

b) 12

c) 5

d) 10

Solution:

74) How long can a battery last with capacity of 50 ampere-hour running an equipment of 5 amperes?

a) 250 hrs

b) 25 hrs

c) 100 hrs

d) 10 hrs

Solution:

75) ___ is a type of linear voltage used in applications where the load on the unregulated voltage source must be kept constant.

a) A series regulator

b) A shunt regulator

c) A constant current source

d) A shunt current source

Solution:

76) What does the term single-phase indicates?

a) one input

b) one current (one input)

c) one time

d) one voltage (one input)

Solution:

77) How many lithium cells in series are needed for a 12 V battery?

a) 12 cells

b) 4 cells

c) 8 cells

d) 10 cells

Solution:

78) Which class of amplifier is distinguished by the flow of current in the output essentially in 180 degrees pulses?

a) Class C

b) Class B

c) Class A

d) Class D

Solution:

79) Find the ripple factor (Kr) of a sinusoidal signal with peak ripple of 4 volts on an average of 30.

a) 0.094

b) 0.013

c) 0.130

d) 0.94

Solution:

80) Silicon diodes are used in a two-diode full-wave rectifier circuits to supply a load of 12 volts Dc. Assuming ideal diodes and the load resistance is 12 ohms, compute the efficiency of the rectifier in percentage.

a) 5.8

b) 75

c) 95.7

d) 81.2

Solution:

81) ____ is the characteristic of an oscillator that enables it to sustain oscillation after removal of the control stimulus.

a) Momentum

b) Fly-wheel effect

c) Damping

d) Forced oscillations

Solution:

82) The gain of a different amplifier is 10, and all inputs are sine waves with a peak-to-peak amplitude of 10 millivolts. If the single input, differential output, differential amplifier has an output signal taken between the two output terminals. What will be the peak to peak amplitude of the combined output?

a) 20 millivolts

b) 220 millivolts

c) 200 millivolts

d) 2000 millivolts

Solution:

83) It consists of elements inseparably associated and formed on or within a single substrate.

a) Integrated circuit (IC)

b) Microsoft

c) Module

d) Micro circuit

Solution:

84) IC production method to prevent unwanted interaction between elements within a chip.

a) Evaporation

b) Cathode splittering

c) Isolation

d) Diffusion

Solution:

85) All input signals are waves with a peak amplitude of 10 millivolts. The gain of the differential amplifier is 10. If it is configured as a single input and a single output. What will be the peak-topeak amplitude of the output signal?

a) 110 millivolts

b) 100 millivolts

c) 10 millivolts

d) 1000 millivolts

Solution:

86) How do you turn on a diac?

a) Gate current

b) Breakover voltage

c) Gate voltage

d) Anode voltage

Solution:

87) Find the two stable operating conditions of an SCR?

a) conducting and non-conducting

b) oscillating and quiescent

c) NPN conduction and PNP conduction

d) Forward conducting and reverse conducting

Solution:

88) The term used to describe the process whereby two transistors with positive feedback are used to stimulate the action of the thyristor.

a) Arcing

b) Latching

c) Damping

d) Switching

Solution:

89) In the concept of induction heating in industrial electronics, the eddy current penetrates to greater depths at

a) high frequencies

b) increasing induction

c) decreasing induction

d) low frequencies

Solution:

90) When testing an SCR with an ohmmeter, the SCR will conduct if what two elements are shorted together?

a) Gate and anode

b) Ground and Cathode

c) Gate and Ground

d) Gate and Cathode

Solution:

91) Analysis of the spectrum of light or other form of electromagnetic radiation emitted or absorbed by a substance in order to investigate its structure.

a) Flouroscopy

b) Calligraphy

c) Spectroscopy

d) Spectography

Solution:

92) A triac is a/an ___ equivalent of two SCRs.

a) series

b) inverse-parallel

c) parallel-series

d) parallel

Solution:

93) The purpose of installing thyristors across the incoming power lines to speed the control system is to ___.

a) cause the motor to caution

b) protect drive circuits from high voltage transient surges

c) increase counter-emf

d) all the field winding current to continue flowing

Solution:

94) What is the systematic movement of a radar beam while searching or tracking a target?

a) Scanning

b) Locked on

c) Acquisition

d) Electrolysis

Solution:

95) A new concept in commercial aircraft where computers monitor aircraft systems reporting on their status only if requested by the pilot or if something is wrong and displayed on the screen
when necessary.

a) Virtual cockpit

b) Real cockpit

c) Glass cockpit

d) The cockpit

Solution:

96) Pentagon planners computer based advanced speech recognition system.

a) TOMCAT

b) EAGLE

c) ORION

d) SPHINX

Solution:

97) A TRIAC behaves like two

a) diodes in series

b) resistors and one diode

c) four-layer diodes in parallel

d) inverse parallel connected SCRs with common gate.

Solution:

98) Originally called a double-base diode. It is three terminal, solid-state device that has several advantages over conventional transistor and has only one PN junction.

a) UDT

b) UJT

c) FET

d) MOSFET

Solution:

99) An automatic switch, which is operated by current in a coil, is called _____.

a) SCS

b) Relay

c) SCR

d) Laser

Solution:

100) If the gain of an amplifier without feedback is 10 and with negative feedback is 8, then the feedback fraction is

a) 0.025

b) 0.9

c) 0.8

d) 0.225

Solution:

### Complete List of Electronics Engineering Pre-Board Exams

Electronics Engineering Pre-Board Exams
Module 1: Electronics Engineering Exam 1                   Answer key: EXAM 1
Module 2: Electronics Engineering Exam 2                   Answer key: EXAM 2
Module 3: Electronics Engineering Exam 3                   Answer key: EXAM 3
Module 4: Electronics Engineering Exam 4                   Answer key: EXAM 4
Module 5: Electronics Engineering Exam 5                   Answer key: EXAM 5
Module 6: Electronics Engineering Exam 6                   Answer key: EXAM 6
Module 7: Electronics Engineering Exam 7                   Answer key: EXAM 7
Module 8: Electronics Engineering Exam 8                   Answer key: EXAM 8
Module 9: Electronics Engineering Exam 9                   Answer key: EXAM 9
Module 10: Electronics Engineering Exam 10                   Answer key: EXAM 10