NNPC Recruitment Past Questions & Answers – General Knowledge

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The NNPC recruitment past questions and answers will go a long way to prepare you for the forthcoming NNPC Recruitment Examination.

NNPC Recruitment Past Questions & Answers – General Knowledge

General (Physics, Chemistry, ICT) Past questions & Answers
1)       Watt’s law states the relationships of power to energy.
A.      True
B.      False
Answer: Option B Explanation:
Watt’s law gives relationship between power to current, voltage and resistance.
2) Energy is equal to power multiplied by voltage. A. True
B.      False
Answer: Option B Explanation:
Energy = Power*Time (not multiply by voltage).
P = VI.
P = (V^2)/R.
P = (I^2)*R.
3) The capacity of a battery is measured in milliamperes. A. True
B.      False
Answer: Option B Explanation:
Battery capacity is measured in ampere-hours (amp-hours)
4)      The power rating of a resistor determines the minimum power that it can handle safely
A.      True
B.      False
Answer: Option B
5)      The joule is a unit of energy.
A.      True
B.      False
Answer: Option A
6)      If you used 400 W of power for 30 h, you have used
A.      1.3 kWh
B.      13.3 kWh
C.      1.2 kWh
D.     12 kWh
Answer: Option D Explanation:
The power is multiplied by time then the energy is: E = P*T.
E = 400*30 = 12*10^3.
= 12KWH.
7) At the end of a 14 day period, your utility bill shows that you have used 18 kWh. What is your average daily power?
A. 1.286 kWh B. 12.85 kWh C. 535 kWh D. 252 kWh
Answer: Option A Explanation:
18 kwh for 14 days.
For one day power consumption is = 18/14.
= 1.2857
8)      A 15 V source is connected across a 12 O resistor. How much energy is used in three minutes?
A.      938 Wh
B.      0.938 Wh
C.      56.25 Wh
D.     5.6 Wh
Answer: Option B Explanation:
As per ohm’s law,
R = V / I
I = V / R
= 15 / 12
= 1.25 A
And Power P = V * I
= 15*1.25
= 18.75 w
Given duration is 3 miniute i.e. 3 / 60 hour
Therefore, Watt-hour = 18.75 * (3 / 60) = 0.9375
9)      A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating is
A.      0.58 Ah
B.      2.1 Ah
C.      21 Ah
D.     58 Ah
Answer: Option C Explanation:
The capacity of battery generally expressed in AH, so that in this case AH is 6A*3.5H=21AH
10) A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is
A. 8.57%
B. 42.85%
C. 4.28%
D. 85.7%
Answer: Option D
Explanation:
Efficiency=output/input
=. 6\.7
=. 857
% efficiency =. 857*100
= 85.7%
11) A certain appliance uses 350 W. If it is allowed to run continuously for 24 days, how many kilowatt-hours of energy does it consume?
A. 20.16 kWh B. 201.6 kWh C. 2.01 kWh D. 8.4 kWh
Answer: Option B Explanation:
Kwh = (350*24*24)/1000
= 201.6kWh
12)    In 0.025 W, there are
A.      25 kW
B.      0.00025 mW
C.      2,500 µW
D.     25 mW
Answer: Option D Explanation:
0.025w=25*10^-3=25mw
13)    When the pointer of an analog ohmmeter reads close to zero, the resistor being measured is
A.      overheated
B.      shorted
C.      open
D.     reversed
Answer: Option B
Explanation:
r=0 when short circuited r=infinity(high) when open circuited.
14)    A 33 O half-watt resistor and a 330O half-watt resistor are connected across a 12 V source. Which one(s) will overheat?
A.      33
B.      330
C.      both resistors
D.     neither resistor
Answer: Option D Explanation:
15)    The current in a given circuit is not to exceed 24 A. Which value of fuse is best?
A.      a fuse is not necessary
B.      10 A
C.      24 A
D.     20 A
Answer: Option C Explanation:
Yes, answer is 24A. If current flow exceeds 24A then fuse works and breaks up the circuit, till then circuit is safe
16)    An ohmmeter is an instrument for measuring
A.      current
B.      voltage
C.      resistance
D.     wattage
Answer: Option C
17)    An ammeter is an electrical instrument used to measure
A.      current
B.      voltage
C.      resistance
D.     none of the above
Answer: Option A
18)    A circuit breaker is a
A.      fuse
B.      switch
C.      resettable protective device
D.     resistor
Answer: Option C Explanation:
Circuit breaker break the circuit when it sense any abnormal condition in the circuit using relay. Relay is a very important component in a circuit breaker.
19) A neutral atom with an atomic number of five has how many electrons? A. 1
B.      5
C.      none
D.     depends on the type of atom
Answer: Option B Explanation:
1 st orbit = 2 electrons
2 nd orbit = 3 electron
atomic no = no.of protons in nucleus
there fore 2+3=5
20)    A wiper is the sliding contact in a
A.      switch
B.      photoconductive cell
C.      thermistor
D.     potentiometer
Answer: Option D Explanation:
Wiper is connected on metal rod of potentiometer, we can vary it.
21)    If there is 6 A of current through the filament of a lamp, how many coulombs of charge move through the filament in 1.75 s?
A. 10.5 C B. 105 C C. 3.4 C D. 34 C
Answer: Option A Explanation:
Charge(Q) = current/time(sec)=i/t so i = Q/t
Q = i*t=(6*1.75) Q = 10.5
22)    A multimeter measures
A.      current
B.      voltage
C.      resistance
D.     current, voltage, and resistance
Answer: Option D
23) A material that does not allow current under normal conditions is a(n) A. insulator
B.      conductor
C.      semiconductor
D.     valence
Answer: Option A
24)    The colored bands for a 4,700 ohm resistor with a ten percent tolerance are
A.      yellow, violet, red, gold
B.      yellow, violet, orange, gold
C.      yellow, violet, red, silver
D.     orange, violet, red, silver
View answer Discuss in forum
Answer: Option C
E
xplanation:
BLACK-0
BROWN-1
RED -2
ORANGE-3
YELLOW-4
GREEN-5
BLUE -6
VIOLET-7
GREY -8
WHITE-9
The first band gives the first digit.
The second band gives the second digit.
The third band indicates the number of zeros.
The fourth band is used to shows the tolerance (precision) of the resistor
4700 means,
4 =yellow
7 =violet
00 =red(10^2)
Ten percent tollerance =silver
So, =4700.
25)    Eight-tenths coulomb passes a point in 4 s. The current in amperes is
A. 1.6 A B. 16 A C. 2 A
D.     0.2 A
Answer: Option D Explanation:
Q = 8/10 given;
t = 4 s
Now current i = Q / t i = (8/10)/4
i = 2/10;
i = 0.2 A
26)    The tool material, for faster machining, should have
A. wear resistance
B. red hardness
C. toughness
D. all of the above
Answer D
27)    Dielectric is used in
A. electro-chemical machining
B. ultra-sonic machining
C. electro-discharge machining
D. laser machining
Answer C
28)    In a single point tool, the angle between the surface of the flank immediately below the point and a line drawn from the point perpendicular to the base, is known as
A. side relief angle B. end relief angle C. back rake angle D. side rake angle Answer B
29)    The type of reamer used for reaming operation in a blind hole, is
A. straight fluted reamer
B. left hand spiral fluted reamer
C. right hand spiral fluted reamer
D. any one of the above
Answer C
30)    In centreless grinders, the maximum angular adjustment of the regulating wheel is
A. 5º
B. 10º C. 15º D. 20º
Answer B
31)    The lathe spindles are usually made hollow and provided with
A. internal taper
B. external taper
C. internal and external taper
D. no taper
Answer A
32)    Which of the following parameters influence the axial feed rate in centreless grinding?
A. Regulating wheel diameter
B. Speed of the regulating wheel
C. Angle between the axes of grinding and regulating wheels
D. all of the above
Answer D
33)    The example of snag grinding is
A. trimming the surface left by sprues and risers on castings
B. grinding the parting line left on castings
C. removing flash on forgings
D. all of the above
Answer D
34)    internal gears can be made by
A. hobbing
B. shaping with pinion cutter
C. shaping with rack cutter
Answer B
35) If the diameter of the hole is subject to considerable variation, then for locating in jigs and fixtures, the pressure type of locator used is
A. conical locator
B. cylindrical locator
C. diamond pin lovator
D. vee locator
Answer A
36)    Segmental chips are formed during machining
A. mild steel
B. cast iron
C. high speed steel D. high carbon steel Answer B
37)    The leakage in a refrigeration system using ammonia is detected by
A. halide torch
B. sulphur sticks
C. soap and water D. all of the above Answer B
38)    The process, generally used in summer air conditioning to cool and dehumidify the air, is called
A. humidification
B. dehumidification
C. heating and humidification
D. cooling and dehumidification
Answer D
39)    The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called
A. First law of thermodynamics
B. Newton’s law of cooling C. Newton’s law of heating D. Stefan’s law
Answer B
40)    The rate of heat flow through a body is . The term x/kA is known as
A. thermal coefficient
B. thermal resistance
C. thermal conductivity D. none of the above Answer B
41)    In counter-current flow heat exchangers
A. both the fluids at inlet are in their hottest state B. both the fluids at inlet are in their coldest state C. both the fluids at exit are in their hottest state
D. one fluid is coldest and the other is hottest at inlet
Answer A
42)    The most commonly used method for the design of duct size is the
A. velocity reduction method
B. equal friction method
C. static regain method
D. dual or double method
Answer C
43)    In a shell and tube heat exchanger, baffles are provided on the shell side to
A. improve heat transfer
B. provide support for tubes
C. prevent stagnation of shell side fluid
D. all of the above
Answer D
44)    A refrigerant with the highest critical pressure is
A. R-11
B. R-12
C. R-22
D. Ammonia
45) A condenser of refrigeration system rejects heat at the rate of 120 kW, while its compressor consumes a power of 30 kW. The coefficient of performance of the system will be
A. 1/4
B. 1/3
C. 3
D. 4
Answer D
46) If the energy radiated per second per sq. cm. of the surface for wave lengths lying between ?, and ? + d? is represented by (e?.d?), then e? is called
A. absorptive power
B. emissive power
C. emissivity
D. none of the above
Answer B
47)    The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is called
A. wet bulb temperature
B. dry bulb temperature
C. dew point temperature D. none of the above Answer A
48)    R-12 is generally preferred over R-22 in deep freezers since
A. it has low operating pressures
B. it gives higher coefficient of performance
C. it is miscible with oil over large range of temperatures
D. all of the above
Answer C
49)    The evaporator used in house-hold refrigerators is
A. frosting evaporator
B. non-frosting evaporator
C. defrosting evaporator D. none of the above Answer A
50)    The pressure at the outlet of a refrigerant compressor is called
A. suction pressure
B. discharge pressure
C. critical pressure D. back pressure Answer B
51)    The dry bulb temperature lines, on the psychrometric chart are
A. vertical and uniformly spaced
B. horizontal and uniformly spaced
C. horizontal and non-uniformly spaced
D. curved lines
Answer A
52)    In electrolux refrigerator
A. ammonia is absorbed in hydrogen
B. ammonia is absorbed in water
C. ammonia evaporates in hydrogen D. hydrogen evaporates in ammonia Answer C
53)    Which of the following statement is correct?
A. The constant enthalpy lines are also constant wet bulb temperature lines. B. The wet bulb and dry bulb temperature are equal at saturation condition. C. The wet bulb temperature is a measure of enthalpy of moist air.
D. all of the above
Answer D
54)    Which of the following refrigerant has the maximum ozone depletion potential in the stratophere?
A. Ammonia
B. Carbon dioxide C. Sulphur dioxide D. Flourine
Answer D
55) A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking  1 kW of work input. The refrigerating effect will be
A. 1 kW B. 2 kW C. 3 kW D. 4 kW
Answer D
56)    The automobile radiator is a heat exchanger of
A. parallel flow type B. counter flow type C. cross flow type
D. regenerator type
Answer C
57)    The centrifugal compressors are generally used for refrigerants that require
A. small displacements and low condensing pressures
B. large displacements and high condensing pressures C. small displacements and high condensing pressures D. large displacements and low condensing pressures Answer D
58)    The humidity ratio or specific humidity is the mass of water vapour present in
A. 1 m³ of wet air B. 1 m³ of dry air C. 1 kg of wet air D. 1 kg of dry air Answer D
59) In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
A. Reynold’s number
B. Grashoff’s number
C. Reynold’s number, Grashoff’s number D. Prandtl number, Grashoff’s number Answer D
60)    Which of the following statements is wrong?
A. The heat transfer in liquid and gases takes place according to convection
B. The amount of heat flow through a body is dependent upon the material of the body
C. The thermal conductivity of solid metals increases with rise in temperature
D. Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference.
Answer C
61)    Which one of the following is the effect of blade shape on performance of a centrifugal compressor ?
A. Backward curved blades has poor efficiency
B. Backward curved blades lead to stable performance
C. Forward curved blades has higher efficiency
D. Forward curved blades produce lower pressure ratio
Answer D
62)    In a series RLC circuit, the larger reactance determines the net reactance of the circuit.
A.      True
B.      False
Answer: Option A Explanation:
In a series RLC circuit, the net reactance= inductive reactance Xl-capacitive reactance Xc. therefore if any one reactances is large enough then other can be neglected and that primarily determines almost the net reactance of the circuit….
63) Resonance is a condition in a series RLC circuit in which the capacitive and inductive reactances are equal in magnitude.
A.      True
B.      False
Answer: Option A Explanation:
Because at resonance XL=XC.
64) A certain series resonant circuit has a bandwidth of 2 kHz. If the existing coil is replaced with one having a higher value of Q, the bandwidth will
A. increase
B. remain the same
C. decrease
D. be less selective Answer: Option C Explanation:
We know, Bw = F/Q.
When Q increase, the bandwidth decreases.
65) In a certain series resonant circuit, VC = 125 V, VL = 125 V, and VR = 40 V. The value of the source voltage is
A. 125 V B. 250 V C. 290 V D. 40 V
Answer: Option D Explanation:
Vs ^2 = (Vr^2 + (Vl-Vc)^2 ), For resonance , Vl = Vc ,
So , Vs = Vr.
66)    To tune a parallel resonant circuit to a higher frequency, the capacitance should be
A. increased B. decreased C. left alone
D.     replaced with inductance
Answer: Option B Explanation:
Because fr=1/(2*pi*root(LC)).
67)    A 24 O resistor, an inductor with a reactance of 120 O, and a capacitor with a reactance of 120
O are in series across a 60 V source. The circuit is at resonance. The voltage across the inductor is
A.      60 V
B.      660 V
C.      30 V
D.     300 V
Answer: Option D Explanation:
As in resonace impedance equal to resistance
Current = 60/24 = 2.5
Vtg across inductor = 120*2.5 = 300V
68)    If the value of C in a series RLC circuit is decreased, the resonant frequency
A.      is not affected
B.      increases
C.      is reduced to zero
D.     decreases
Answer: Option B Explanation:
69) A resonant circuit has a lower critical frequency of 7 kHz and an upper critical frequency of 13 kHz. The bandwidth of the circuit is
A. 7 kHz B. 13 kHz C. 20 kHz D. 6 kHz
Answer: Option D Explanation:
B.W = f2-f1.
B.W = 13-7 = 6.
70)    A 90 O resistor, a coil with 30 O of reactance, and a capacitor with 50 O of reactance are in series across a 12 V ac source. The current through the resistor is
A.      9 mA
B.      90 mA
C.      13 mA
D.     130 mA
Answer: Option D Explanation:
V=IR I=V/R
So.. R is nothing but Z (R=Z) Z=sqrrt(R^2+( xl-xc)) OR (R^2+(xc-xl)) z=sqrrt_(90^2+(50-30^2) Z=SQRRT(8100+400)
z=92.195
I=V/Z=12/92.195=0.13015=130mA.
71)                controls the way in which the computer system functions and provides a means by which users can interact with the computer.
A.   The operating system
B.   The motherboard
C.   The platform
D.   Application software
Answer: A
72) The difference between people with access to computers and the
Internet and those without this access is known as the:
A.   digital divide.
B.   Internet divide. C.   Web divide.
D.   cyberway divide.
Answer: A
73) Servers are computers that provide resources to other computers connected to a:
A.   mainframe
B.   supercomputer
C.   network
D.   client
Answer: C
74) Word processing, spreadsheet, and photo-editing are examples of:
A.   application software. B.   system software.
C.   operating system software.
D.   platform software.
Answer: A
75) A                is approximately one billion bytes.
A.   bit
B.   kilobyte C.   gigabyte D.   megabyte
Answer: C
76) All of the following are examples of input devices EXCEPT a:
A.   scanner B.   mouse C.   printer
D.   keyboard
Answer: C
77) Computers use the                language to process data.
A.   relational B.   megabyte C.   binary
D.   processing
Answer: C
78) In the binary language each letter of the alphabet, each number and each special character is made up of a unique combination of:
A.   eight bytes.
B.   eight characters. C.   eight bits.
D.   eight kilobytes.
Answer: C
79)                is data that has been organized or presented in a meaningful way.
A.   A process
B.   Information
C.   Software
D.   Storage
Answer: B
80) All of the following are examples of real security and privacy risks
EXCEPT:
A.   Viruses
B.   Identity theft. C.   Hackers
D.   Spam
Answer: D
81) Which of the following is an input device?
A.   Mouse
B.   Keyboard
C.   Scanner
D.   All the above
Answer: D
82) The set of instructions that tells the computer what to do is
A.   Softcopy B.   Software C.   Hardware D.   Hardcopy
Answer: B
83) Which of the following stores more data?
A.   DVD
B.   CD ROM
C.   Floppy Disk
D.   CD RW
Answer: A
84) —- is the heart of the computer and this is where all the computing is done.
A.   Keyboard
B.   Monitor
C.   Central Processing Unit
D.   Printer
Answer: C
85) One byte is equivalent to
A.   8 bit B.   16 bit C.   32 bit D.   64 bit
Answer: A
86) To move forward through the tabs
A.   CTRL+TAB
B.   CTRL+SHIFT+TAB C.   SHIFT+TAB
D.   None of these
Answer: A
87) Personal computers can be connected together to form a
A.   server
B.   network
C.   supercomputer D.   Enterprise Answer: B
88) Choose the smallest memory size
A.   kilobyte
B.   megabyte C.   gigabyte D.   terabyte Answer: A
89) The steps and tasks needed to process data, such as responses to questions or clicking an icon, are called:
A.   instructions
B.   operating system
C.   application software
D.   system unit
Answer: A
90) The operating system is the most common type of                software. A. system
B.   communication
C.   application
D.   word-processing
Answer: A
91) The ability to recover and read deleted or damaged files from a criminals computer is an example of a law enforcement specialty called:
A.   simulation B.   animation C.   robotics
D.   computer forensics.
Answer: D
92) The base of the hexadecimal number system is
A. 2
B. 8
C. 10
D. 16
Answer: D
93) Computer software includes
A.   Packaged programs
B.   Application programs
C.   Operating system programs
D.   All of these
Answer: D
94) The Operating System Manages
A.   Processes
B.   Memory
C.   Disks and I/O devices
D.   All of the above
Answer: D
95) Allocation of a resources in a time dependent manner to several program simultaneously called
A.   multi user
B.   multi tasking
C.   time sharing
D.   None of these.
Answer: C
96) Data that are accumulated and processed in group called
A.   Group processing B.   Batch Processing C.   Time sharing
D.   None of these.
Answer: B
97) Multiprocessing supports more then one………………at the same time
A.   User
B.   Process
C.   Hardware
D.   None of these. Answer: B
98) Which of the following are true about firewalls? A.   Follows a set of rules
B.   Can be either a hardware or software device
C.   Filters network traffic
D.   All the above
Answer: D
99) What are the four things needed to connect to the Internet? A.   Monitor, keyboard, mouse, modem
B.   Telephone line, PDA, modem and computer
C.   Telephone line, modem, computer, and an ISP
D.   Modem, computer, PDA and ISP
Answer: C
100) 1024 bytes equals: A.   1 KB
B.   1 MB
C.   1 GB
D.   1 TB
Answer: A
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