WorksheetsELEX Pre-Board Exam 2
Total questions: 100
Worksheet time: 3hrs 20mins
Name
Class
Date
1.
What is a group of circuits that provides timing and signals to all operation in the computer?
a)
Output unit
b)
Memory unit
c)
Control unit
d)
Input unit
2.
Where does voltage generated in a DC generator depend?
a)
Field resistance and flux
b)
Field and armature currents
c)
Flux and speed
d)
Speed and field resistance
3.
__________ is the most influential factor in the switching speed of saturated bipolar transistor
a)
Charge stored
b)
Collector current
c)
HFE
d)
Base current
4.
What is a pi-network?
a)
A Power Incidence Network
b)
A network consisting of one inductor and two capacitors or two inductors and one capacitor
c)
A network consisting entirely of four inductors or four capacitors
d)
An antenna matching network that is isolated form ground
5.
__________ is the property of a material which opposes creation of magnetic flux?
a)
Resistance
b)
Permeance
c)
Reluctance
d)
Conductance
6.
The purpose of cells connected in parallel is to
a)
increase internal resistance
b)
increase voltage output
c)
decrease current capacity
d)
increase current capacity
7.
What does SI magnetic flux refer?
a)
Weber
b)
Flux
c)
Maxwell
d)
Lines
8.
__________ is a type of linear regulator used in applications requiring efficient utilization of the primary power source.
a)
A series regulator
b)
A shunt regulator
c)
A constant current source
d)
A shunt current source
9.
When a switch is closed, it has a total resistance of
a)
1000 ohms at room temperature
b)
unstable
c)
infinity
d)
zero
10.
How many turns are needed to produce a magnetizing force of 5000 A.t. for a coil of 50 amperes?
a)
1,000 turns
b)
5,000 turns
c)
100 turns
d)
500 turns
11.
When an SCR is triggered or on condition, its electrical characteristics are similar to what other solid-state device (as measured between its cathode and anode)?
a)
The junction diode
b)
The varactor diode
c)
The tunnel diode
d)
The hot-carrier diode
12.
What special type of diode is capable of both amplification and oscillation?
a)
Point contact diode
b)
Junction diode
c)
Zener diode
d)
Tunnel diode
13.
A static memory generally contains
a)
electrons
b)
positive ions
c)
row decoders
d)
holes
14.
Which is the majority carrier in an N-type semiconductor?
a)
Electrons
b)
Positive ions
c)
Negative ions
d)
Holes
15.
Steel is hard to magnetize because of its _______.
a)
high retentivity
b)
low permeability
c)
high permeability
d)
high density
16.
When you increase the resistance in a circuit, the flows of electrons will ______
a)
flow faster
b)
be constant
c)
be decreased
d)
be stopped
17.
Current in a chemical cell refers to the movement of ________
a)
negative ions only
b)
negative and positive ions
c)
positive ions only
d)
negative hole charge
18.
What is the effect of light in a photodiode?
a)
Reverse current
b)
Limits flow of current
c)
Forwards current
d)
Renders unstable current
19.
What is the effect in terms of bandwidth when the Q of a single-tune stage is doubled?
a)
Doubled
b)
The same
c)
Halved
d)
Four times
20.
___________ is the dc motor control senses.
a)
Resistance
b)
Counter emf
c)
Field voltage
d)
Armature current
21.
What is the range of voltage rating available in zener diodes?
a)
2.4 volts to 200 volts
b)
1.2 volts to 7 volts
c)
3 volts to 2000 volts
d)
1.2 volts to 5.6 volts
22.
Find which type of network provides the greatest harmonic suppression.
a)
Pi-network
b)
Pi-L-network
c)
Inverse-Pi-network
d)
L-network
23.
What type of transformer that is used to protect technicians and operators from deadly electrical shock?
a)
Absorber transformer
b)
Step-down transformer
c)
Step-up transformer
d)
Isolation transformer
24.
What is residual magnetism?
a)
The external magnetic field when the current is flowing through the exciting coil.
b)
The flux density, which exist in the iron core when the magnetic field intensity is reduced to zero.
c)
The flux density, which exist in the iron core when the magnetic field intensity is at its maximum value.
d)
The flux density when the magnetic core is saturated.
25.
When batteries have cells connected in series the effect is
a)
reduced output voltage
b)
increased current supply
c)
increased voltage supply
d)
reduced internal resistance
26.
How many OP-AMPS does window comparator require?
a)
2
b)
4
c)
3
d)
1
27.
What is the memory element used in clocked sequential logic circuit?
a)
Gates
b)
Flip-flop
c)
Static-RAM
d)
Read-only memory
28.
Semiconductors which are considered to be “low power” or “small signal” usually have power dissipation ratings of
a)
1 watt or less
b)
5 watts or less
c)
exactly 1 watt
d)
10 watt or less
29.
________ for a transistor to be cut-off
a)
Maximum current flows from emitter to collector
b)
The transistor is at its operating point
c)
No current flows from emitter to collector
d)
There is no base current
30.
A __________ is an instruction in a source language that is to be replaced by a defined sequence of instructions in the same source language
a)
statement
b)
source code
c)
mnemonic
d)
macro-instruction
31.
Common-base (CB) amplifier has ______ compared to common-emitter and common collector amplifiers.
a)
a higher input resistance
b)
a larger current gain
c)
a lower input resistance
d)
a larger voltage gain
32.
_________ currents are wasteful currents which flow in cores of transformers and produces heat.
a)
Residual
b)
Eddy
c)
Sneak
d)
Magnetizing
33.
Which of the following photocell is most sensitive to?
a)
Radio waves
b)
Sound waves
c)
Light waves
d)
Heat waves
34.
What is the resonant frequency of a circuit when L of 1 microhenry and C of 10 picofarads are in series?
a)
15.9 MHz
b)
50.3 MHz
c)
50.3 kHz
35.
What is the law that determines polarity of an induced voltage?
a)
Norton’s Law
b)
Thevenin’s Law
c)
Lenz Law
d)
Faraday’s Law
36.
The science of physical phenomena at very low temperatures, approaching absolute zero is called ____________
a)
Crytanalysis
b)
Cybernetics
c)
Temperature inversion
d)
Cryogenics
37.
If a dry cell has an internal resistance of 0.50 ohm and an emf of 2 volts, find power delivered in a one ohm resistor?
a)
1.33 watts
b)
1.66 watts
c)
3.66 watts
d)
1.77 watts
38.
What happens in the resistance of copper wired when its temperature is raised?
a)
Decreased
b)
Steady
c)
Increase
d)
Zero
39.
Refers to the part of computer that performs mathematical operations
a)
CPU
b)
Flip-flop
c)
Assembly Language
d)
ALU
40.
________ is called a memory device which holds fixed set of data in a circuit.
a)
RAM
b)
Register
c)
Logic
d)
ROM
41.
When a voltage of 100 V at 50 Hz is applied to a choking coil A, the current taken is 8A and the power is 120 W, when applied to a coil B, the current is 10 A and the power is 120 W. What power will be taken when 100 V is applied to the two coils connected in series?
a)
4737 W
b)
140 W
c)
70 W
d)
1454 W
42.
The current needed to operate a soldering iron which has a rating of 600 watts at 110 volts is
a)
5.455 A
b)
66,000 A
c)
18,200 A
d)
182 A
43.
An interval required to address and read out memory word
a)
Propagation delay
b)
Pulse duration
c)
Settling time
d)
Access time
44.
When a logic circuit rejects an unwanted signal, this is termed as ________
a)
logic levels
b)
noise margin
c)
power consumption
d)
propagation delay
45.
What is responsible for the phenomenon when voltages across reactances in series can often be larger than the voltage applied to them?
a)
Capacitance
b)
Resistance
c)
Conductance
d)
Resonance
46.
How many symbols do hexadecimal digital number system used?
a)
16
b)
4
c)
8
d)
32
47.
What is the equivalent of decimal 47 in binary?
a)
111011
b)
111101
c)
110111
d)
101111
48.
What is the logic circuit having two or more inputs but only one output with high output if any or all inputs are high, with low output only when all inputs are low?
a)
AND gate
b)
OR gate
c)
NOR gate
d)
NAND gate
49.
Determine which is not a dynamic test instrument
a)
Oscilloscope
b)
Logic monitor
c)
Logic
50.
How much voltage regulation does commercial power supply have?
a)
10% and above
b)
Within 1%
c)
15% and above
d)
10%
51.
________ is called an electronic transfer from one stage to the next.
a)
Coupling
b)
Swamping
c)
Doping
d)
Mixing
52.
_______ capability is analogous to permeance.
a)
Admittance
b)
Conductance
c)
Reluctance
d)
Resistance
53.
Which is a common use for point-contact diode?
a)
As a constant current source
b)
As a constant voltage source
c)
As an RF detector
d)
As a high voltage rectifier
54.
Which of the following is not a secondary type cell?
a)
Lithium
b)
Lead-acid
c)
Silver cadmium
d)
Silver-zinc
55.
What do you call the piece of equipment in an oscilloscope used to indicate pulse condition in a digital logic circuit?
a)
Logic probe
b)
Probe
c)
Electroscope
d)
Galvanometer
56.
How many bits, binary pattern represent the decimal numbers 0 to 9 in binary coded decimal?
a)
4
b)
1
c)
2
d)
8
57.
Which is the principal characteristic of a varactor diode?
a)
It has a very high PIV
b)
It has a negative resistance region
c)
Its internal capacitance varies with the applied voltage
d)
It has a constant voltage under conditions of varying current
58.
What is the law whereby the attraction or repulsion between two magnetic poles is directly proportional to their strength?
a)
Coulomb’s law
b)
Newton’s law
c)
Coulomb’s first law
d)
Norton’s law
59.
Efficient oscillators are those that are class ________.
a)
AB
b)
B
c)
C
d)
A
60.
_______ refers to a circuit that stores pulses and produces an output pulse when specified number of pulses is stored.
a)
Counter
b)
Register
c)
Flip-flop
d)
Buffer
61.
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
62.
_________ is a linear electronic voltage regulator
a)
A regulator that has a ramp voltage at its output
b)
A regulator in which the control device is switched on or off, with the duty cycle proportional to the line or load conditions
c)
A regulator in which the pass transistor switches from the “off” state to the “on” state
d)
A regulator in which the conduction of a control element is varied in direct proportion to the voltage or load current.
63.
The particles that make up the lattice in ionic crystal
a)
Molecules
b)
Ions
c)
Electrons
d)
Neutron
64.
Parallel cells have the same voltage as one cell but have _______.
a)
unstable resistance
b)
less current capacity
c)
fluctuating power output
d)
more current capacity
65.
A digital word consisting of only four bits is called a
a)
dibit
b)
quad
c)
pixel
d)
nibble
66.
The reason for the thin layer of varnish over the copper coil pattern is to prevent
a)
oxidizing
b)
flux
c)
corrosion
d)
dioxide
67.
_________ is the output voltage of a carbon-zinc cell.
a)
3.5 V
b)
2.5 V
c)
1.5 V
d)
0.5 V
68.
Speed of a logic circuit is normally expressed as ________
a)
logic levels
b)
speed immunity
c)
propagation delay
d)
power consumption
69.
_______ is the term used to express the ratio of the change in the dc collector current to a change in base current in a bipolar transistor.
a)
Gamma
b)
Beta
c)
Alpha
d)
Delta
70.
_______ refers to a program that translates and then immediately executes statements in a high level language.
a)
Interpreter
b)
Synchronous
c)
Interface
d)
Operating system
71.
__________ is the property of magnetic materials which retain magnetism after magnetizing force is withdrawn.
a)
Reluctivity
b)
Resistivity
c)
Retentivity
d)
Conductivity
72.
A ________ is a junction field effect transistor with a Schottky barrier instead of a normal semiconductor junction.
a)
biFET
b)
MOSFET
c)
MESFET
d)
JUGFET
73.
Term used for response in an electrical circuit.
a)
The frequency at which power factor is at a minimum
b)
The highest frequency that will pass current
c)
The frequency at which capacitive reactance equals inductive reactance
d)
The lowest frequency that will pass current
74.
_________ is the progressive decay with time in the amplitude of the free oscillation in a circuit.
a)
Decrement
b)
Pulse decay time
c)
Damping
d)
Dancing
75.
What do you call a circuit that changes pure binary code into ASCII?
a)
Decoder
b)
Encoder
c)
Demultiplexer
d)
Code converter
76.
Which of the following statement is incorrect?
a)
Open transistor has three (3) terminals
b)
Transistors have three (3) terminals
c)
Potentiometer has three (3) terminals
d)
Typical power rating of carbon-composition resistors ranged from 0.001 W to 0.1 W
77.
Which statement is not true?
a)
The internal resistance of a cell limits the amount of output current
b)
Two electrodes of the same metal provide the highest voltage output
c)
Secondary cell can be recharged
d)
The negative terminal of a chemical cell has a charge of excess electrons
78.
What type of circuit whose parameters are constant which do not change with voltage of current?
a)
Lumped circuit
b)
Tuned circuit
c)
Reactive circuit
d)
Linear circuit
79.
__________ is gaseous tube which uses a pool of liquid mercury as its cathode.
a)
Thyratron
b)
Phanotron
c)
Klystron
d)
Ignition
80.
What do you call an electromagnet with its core in a form of magnetic ring?
a)
Polarization
b)
Irradiation
c)
Toroid
d)
Doping
81.
_________ is the procedure by which an atom is given a net charge by adding or taking away of electron.
a)
Polarization
b)
Irradiation
c)
Ionization
d)
Doping
82.
What do you call an electronic component that is a non-linear resistor and its resistance is function of the voltage across it?
a)
Triac
b)
IC
c)
Varistor
d)
Thyristor
83.
Find the half-power bandwidth of a resonant circuit which has a resonant frequency of 1.8 MHz and a Q of 95.
a)
189 Hz
b)
1.89 kHz
c)
58.7 kHz
d)
18.9 kHz
84.
A dynamic memory will store information
a)
as long as power is applied to the memory
b)
as long as power is applied and the memory is refreshed periodically
c)
even when power is not applied to the memory
d)
when power is applied at regular intervals
85.
The energy of an oscillator can be source by _________
a)
coupling a small coil close to the tube
b)
capacitance of inductive coupling from tuned circuit
c)
inserting resistor in the grid circuit
d)
connecting capacitor across the supply
86.
Refers to that part of computer that interprets and executes instructions
a)
ACC
b)
ALU
c)
CPU
d)
Compiler
87.
What is the gain of a vacuum tube having the following parameter 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
88.
__________is the region in a transistor that is heavily doped
a)
Collector
b)
Ground
c)
Base
d)
Emitter
89.
Which class of amplifier has the highest linearity and least distortion
a)
Class A
b)
Class AB
c)
Class C
d)
Class B
90.
_________ is the unit of reluctance.
a)
Gauss
b)
Weber
c)
Maxwells
d)
At/Wb
91.
Find the value of voltage regulation having a dc voltage of 67 V without load and with full load current drawn the output voltage drops to 42 V.
a)
59.5 %
b)
15.9 %
c)
62.6 %
d)
32.5 %
92.
What is the reason why more cells can be stored in a given area with dynamic cells?
a)
They consume less power
b)
They are smaller
c)
They are larger
d)
They travel faster
93.
Which of the following is a characteristic of cascaded amplifier?
a)
Double each amplifier’s gain
b)
Each amplifiers gain is increased
c)
Increased overall gain
d)
Total gain is decreased
94.
How do you determine if diode is defective?
a)
Diode resistance is either very low or very high on either direction
b)
High current
c)
Very low current
d)
High voltage
95.
Avalanche breakdown is primarily dependent on the phenomenon of
a)
doping
b)
collision
c)
recombination
d)
ionization
96.
What network facility is used to interconnect distinct networks physically?
a)
Relays
b)
Routers
c)
Repeaters
d)
Bridges
97.
Diagram showing procedures which are followed and actions taken is called
a)
functional block diagram
b)
circuit diagram
c)
flow chart
d)
schematic diagram
98.
Find the dielectric constant of air
a)
Approximately 1
b)
Approximately 0
c)
Approximately 2
d)
Approximately 4
99.
__________ refers to the term remote sensing with regard to a linear voltage regulator.
a)
The feedback connection to the error amplifier is made directly to the load
b)
The load connection is made outside the feedback loop
c)
The error amplifier compares the input voltage to the reference voltage
d)
Sensing is accomplished by wireless inductive loops
100.
Transition region refers to ________ with regard to transistor.
a)
the area of maximum N-type charge
b)
the area maximum P-type
c)
the point where wire leads are connected to the P or N type material
d)
an area of low charge density around P-N junction
100 %
