Quiz: Electrical Engineering 4 June 2020

Quiz: Electrical Engineering
Exam: UPPSC-AE
Topic: Single phase induction motor

Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. Speed higher than synchronous speed can be held by
(a) Line voltage control
(b) rotor slip power control
(c) rotor resistance control
(d) frequency control

Q2. In a slip power recovery scheme for 3 phase induction motor, if slip power is
(a) returned to supply, constant power drive is obtained
(b) added to the main shaft, constant power drive is obtained
(c) subtracted from the main shaft, constant torque drive is obtained
(d) obtained from the supply, constant torque drive is obtained

Q3. During plugging of an induction motor
(a) phase sequence is reverted
(b) a dc source is connected to stator
(c) one phase is open circuited
(d) power is fed back to mains

Q4. In dynamic breaking of 3 phase induction motors
(a) the supply terminals of any two stator phases are interchanged
(b) any two stator terminals are earthed
(c) the stator terminals are switched over to a dc source from the ac supply
(d) a dc voltage is injected in the rotor circuit

Q5. The stator of 2/4 pole changing cage motor is initially wound for 2 poles. The reconnection of the stator winding to 4-pole through a changeover switch, while the motor is running would result in
(a) constant torque drive
(b) constant hp drive
(c) plugging to stand still
(d) regenerative breaking to half the original speed.

Q6. A squirrel cage induction motor runs slow, probably cause could be
(a) low voltage
(b) short stator coil
(c) one phase open
(d) Any of the above

Q7. Three phase induction motor should preferably be mounted on
(a) wooden structure
(b) PVC platform
(c) solid concreate foundation
(d) none of the above

Q8. The factors to be considered in the selection of motors is/are
(a) voltage rating of motor
(b) kW output rating of motor
(c) speed and frame enclosure size
(d) all of the above

Q9. Induction generators deliver power at
(a) leading power factor only
(b) lagging power factor only
(c) leading as well as lagging power factor
(d) unity power factor only

Q10. What is the rotor copper loss of a 3 phase 550 volts, 50 Hz, 6 pole induction motor developing 4.1 kW at the shaft with mechanical loss of 750 W T 970 rpm?
(a) 275 W
(b) 150 W
(c) 100 W
(d) 250 W

Solutions
S1. Ans. (b)
Sol. rotor slip power control are best suited for mentioned situation.

S2. Ans. (b)
Sol. added to the main shaft, constant power drive is obtained

S3. Ans. (a)
Sol. phase sequence is reverted for desired result quickly.

S4. Ans. (c)
Sol. the stator terminals are switched over to a dc source from the ac supply

S5. Ans. (d)
Sol. regenerative breaking to half the original speed.

S6. Ans. (d)
Sol. All the condition result in slow running of motor. Over load and open stator coil may be additional reason for slow running.

S7. Ans. (d)
Sol. solid concreate foundation

S8. Ans. (d)
Sol. All the mentioned factors should be considered.

S9. Ans. (a)
Sol. Induction generators deliver power at leading power factor only.

S10. Ans. (b)
Sol. Synchronous speed,
Ns = 120f/P
=(120×50)/6 = 1000 rpm
=(N_s-N)/N_s = (1000-970)/1000
=0.03
Mechanical Power developed,
Pmech = Shaft power + mechanical loss
=4100+750 W
= 4850 W
Rotor copper loss,
= s/(1-s) ×4850 W
= 150 W

Quiz:Mechanical Engineering 04 June 2020

Quiz: Mechanical Engineering
Exam: UPPSC AE
Topic: Manufacturing Engineering

Each question carries 3 mark.
Negative marking: 1 mark
Time: 10 Minute

Q1. The atmosphere required in the furnace for nitriding the steel component is of
(a) Liquid nitrogen
(b) Nascent nitrogen
(c) Ammonia
(d) Graphite

Q2. Refractoriness of the moulding sand can be increased by
(a) Increasing the grain size
(b) Decreasing the grain size
(c) Increasing the water content
(d) Increasing the clay content

Q3. Which condition is non-favourable for continuous chips?
(a) Low feed and depth of cut
(b) Brittle work piece
(c) High speed
(d) High back rack angle

Q4. Swab is
(a) a welding defect
(b) a tool used in foundry
(c) a gear cutter
(d) a forging die

Q5. In submerged arc welding, an arc is produced between:
(a) Carbon electrode and the work-piece
(b) Metal electrode and the work-piece
(c) Bare metal electrode and the work-piece
(d) Two tungsten electrodes and the work-piece

Q6. A 50 mm diameter disc is to be punched out from a carbon steel sheet 1.0 mm thick. The diameter of the punch should be
(a) 42.925 mm
(b) 50.00 mm
(c) 50.075 mm
(d) None of these

Q7. Among the following for which operation, the slowest speed is selected in lathe?
(a) Facing
(b) Taper turning
(c) Thread cutting
(d) Straight turning

Q8. Abrasive grain size of 10 on grinding wheel refers to:
(a) Fine grain wheel
(b) Coarse grain wheel
(c) Medium grain wheel
(d) Very fine grain wheel

Q9. Plug rolling is used to
(a) produce seamless tube
(b) reduce wall thickness and increase diameter of tubes
(c) produce collapsible tubes
(d) increase wall thickness of tubes

Q10. Which type of gears can be manufactured by extrusion process?
(a) Bevel gears
(b) Herringbone gears
(c) Worm gears
(d) None of these

Solutions

S1. Ans.(c)
Sol. The atmosphere required in the furnace for nitriding the steel component is of ammonia. Nitriding is a heat treatment process that diffuse nitrogen into the surface of a metal to create a case-hardened surface.

S2. Ans.(a)
Sol. Refractoriness of the moulding material is the ability to withstand high temperature of molten metal, so that it does not get fused with the metal.
It can be increased by increasing the grain size.

S3. Ans.(b)
Sol. Cutting of a brittle material is non favourable for continuous chips formation. Continuous chips form in ductile material.

S4. Ans.(b)
Sol. Swab is a tool that is used in foundry shop and used for applying water to the mould around the edge of the pattern. This prevents the sand edges from crumbling.

S5. Ans.(c)
Sol. Submerged arc welding, is a common arc welding process, it involves the formation of arc between a continuously fed bare electrode and the work-piece.

S6. Ans.(d)
Sol. We know that clearance of low carbon steel = 3 % of thickness
C=0.03×1
C=0.03 mm
For punching operation,
Punch Size = Blank size-2C=50-2×0.03
Punch size = 50-0.06
Punch size = 49.94 mm

S7. Ans.(c)
Sol. Thread cutting used for forming threads on a workpiece, is done at the slowest speed in lathe machine.

S8. Ans.(b)
Sol. Abrasive grain size of 10 on grinding wheel refers to coarse grain size. Generally, grain sizes of grinding wheel are 10-24(coarse),30-60(medium),80-200(fine) and 220-600(very fine).

S9. Ans.(b)
Sol. Plug rolling is used to reduce the thickness of wall and increase the diameter of the tubes.

S10. Ans.(b)
Sol. Double helical gears or Herringbone gears can be easily manufactured by extrusion process.

Quiz: Electrical Engineering 3 June 2020

Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Instruments & Measurements

Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. For controlling the vibration of the disc of an ac energy meter, damping torque is produced by
(a) eddy current
(b) chemical effect
(c) electrostatic effect
(d) magnetic effect

Q2. Creep error may occur in induction type energy meter due to
(a) incorrect position of brake magnet
(b) incorrect adjustment of position of shading band
(c) over voltage across voltage coil
(d) increase in temperature

Q3. Holes are drilled on the opposite sides of the disc of an induction type energy meter to
(a) avoid creep on no load
(b) balance the disc
(c) dissipate the energy due to eddy current
(d) increase the deflecting torque

Q4. Which of the following is the main cause of creeping in the induction type energy meter?
(a) friction compensation
(b) lag/lead compensation
(c) overload compensation
(d) braking torque producing system

Q5. In a single-phase induction type energy meter, the lag adjustment is done to ensure that
(a) current coil flux lags the applied voltage by 90°
(b) pressure coil flux lags the applied voltage by 90°
(c) pressure coil flux is in phase with the applied voltage.
(d) current coil flux lags the pressure coil flux by 90°

Q6. Which of the following method is used for the measurement of high resistance?
(a) Carey Foster’s bridge method
(b) substitution method
(c) loss of charge method
(d) Potentiometer method

Q7. The sensitivity of Wheatstone bridge depends upon
(a) galvanometer voltage sensitivity
(b) galvanometer resistance
(c) bridge supply voltage
(d) all of the above

Q8. Wagner’s earthing device is used in ac bridge for
(a) shielding the bridge elements
(b) eliminating the stray electrostatic field effect
(c) eliminating the effect of earth capacitance
(d) eliminating the effect of inter-component capacitances

Q9. What should be the main characteristic of the null detector in a bridge measurement?
(a) accuracy
(b) precision
(c) Sensitivity
(d) Resolution

Q10. The dielectric loss of capacitor can be measured by which of the following?
(a) Wien bridge
(b) Owen bridge
(c) Shearing bridge
(d) Maxwell bridge

Solutions

S1. Ans. (a)
Sol. Eddy current

S2. Ans. (c)
Sol. Overvoltage across voltage coil

S3. Ans. (a)
Sol. To avoid creep on no load.

S4. Ans. (a)
Sol. Friction compensation is the right option.

S5. Ans. (b)
Sol. pressure coil flux lags the applied voltage by 90°

S6. Ans. (c)
Sol. Loss of charge method is used to calculate high resistance.

S7. Ans. (d)
Sol. All factors are responsible for sensitivity of Galvanometer

S8. Ans. (c)
Sol. eliminating the effect of earth capacitance

S9. Ans. (d)
Sol. Resolution should be the main characteristic.

S10. Ans. (d)
Sol. Shearing bridge

Quiz Electronics Engineering 2 June 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 02/06/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. A class member declared protected in Java becomes member of subclass of which type?
(a) Public Member
(b) Protected Member
(c) Private Member
(d) Static Member

Q2. How many full adders are required to construct an m-bit parallel adder?
(a) m
(b) m – 1
(c) m/2
(d) m + 1

Q3. Which type of traversal of binary search tree outputs the value in sorted order?
(a) Pre-order
(b) In-order
(c) Post-order
(d) Level-order

Q4. A positive AND gate is also a negative
(a) NAND gate
(b) OR gate
(c) AND gate
(d) NOR gate

Q5. Events A and B are mutually exclusive and have non-zero probability. Which of the following statement is TRUE?
(a) P(AUB) = P(A) + P(B)
(b) P(B’) > P(A)
(c) P(A∩B) = P(A)P(B)
(d) P(B’) < P(A)

Q6. Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R. It will
(a) result in deadlock situation
(b) immediately be granted
(c) immediately be rejected.
(d) None of the above

Q7. Web links are stored within the page itself and when you wish to jump to the page that is linked, we select the hotspot or anchor. This technique is called
(a) Hypertext
(b) Hypermedia
(c) both (a) & (b)
(d) Anchoring

Q8. Which of the following is not a form of main memory?
(a) Instruction opcode
(b) Instruction register
(c) Instruction cache
(d) Translation look-aside buffer

Q9. The number of the edges in a regular graph of degree ‘d’ and ‘n’ vertices is
(a) Maximum of n, d
(b) n + d
(c) nd
(d) nd/2

Q10. Synthesized attribute can easily be simulated by an
(a) LL grammar
(b) ambiguous grammar
(c) LR grammar
(d) None of the above

 

 

SOLUTIONS

S1. Ans.(c)
Sol. A class member which is declared protected from before becomes the Private member of subclass.

S2. Ans.(a)
Sol. For n-bit adder, we require-
(a) (n-1) FA and 1 HA ; or
(b) n FA ; or
(c) (2n-1) HA & (n-1) OR gate.

S3. Ans.(d)
Sol.
(a) In Pre-order , the Root node is visited first, then the Left subtree and at last Right Subtree.
(b) In-order, Left Subtree is visited first , then the Root node, and at last Right Subtree.
(c) Post-order, at first Left Subtree, then Right Subtree and finally Root node.
(d) Level-order is breadth first traversal for the tree.

S4. Ans.(b)
Sol. Positive AND gate has input A, B and output AB.
Negative OR gate will have inverter at both inputs and 1 Output.
So, Output at the negative OR gate is
(A ̅+B ̅ ) ̅ = (AB) ̅ ̅ = AB = Positive AND gate output

S5. Ans.(a)
Sol. By principle of inclusion and exclusion, we get
P(AUB) = P(A) + P(B) + P(A∩B)
In Mutually exclusive condition –
P(A∩B) = 0

So, P(AUB) = P(A) + P(B)

S6. Ans.(b)

immediately be granted

S7. Ans.(c)

Sol. Both (a) and (b)

S8. Ans.(a)
Sol. Instruction opcode tells about what operation to be performed. Excluding it, all are form of a main memory.

S9. Ans.(d)
Sol. Given:
Number of vertices = n
Degree of each vertices or number of neighbours of each vertices = d
So, Total edges = nd/2

S10. Ans.(c)
Sol. Both Synthesized attribute and LR grammar are evaluated in bottom up method. So, these can be simulated easily.

Quiz: Mechanical Engineering 2 June 2020

Quiz: Mechanical Engineering
Exam: ISRO
Topic: Material science

Each question carries 1 mark
Negative marking: 1/3 mark
Time: 10 Minutes
Q1. Atoms are arranged in face centred cubic (FCC) structure as
(a) All eight corners of the cube
(b) All eight corners of the cube and one of the body center
(c) All eight corners of the cube and at the center of each face
(d) All eight corners of the cube and one at the body center with one at the center of each face

Q2. Which of the following are zero dimensional defects?
1. Vacancy
2. Interstitial defect
3. Substitutional defect
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3

Q3. The number of electrons found in the outer most orbit of semi-conductor materials is,
(a) 2
(b) 4
(c) 6
(d) 8

Q4. What is the packing factor of FCC crystal structure?
(a) 0.64
(b) 0.68
(c) 0.74
(d) 0.78

Q5. Which is false statement about annealing?
(a) Annealing is done to relieve stresses
(b) Annealing is done to harden steel slightly
(c) Annealing is done to improve machine characteristics
(d) Annealing is done to soften material

Q6. Pearlite is a combination of:
(a) Ferrite and cementite
(b) Cementite and gamma iron
(c) Ferrite and austenite
(d) Ferrite and iron graphite

Q7. The Burger’s vector lies parallel to the dislocation line along the axis of a line of atoms in the same plane in:
(a) Screw dislocation
(b) Edge dislocation
(c) Cracks
(d) Vacancies

Q8. The atomic bond found in diamond is:
(a) Ionic
(b) Covalent
(c) Metallic bond
(d) None of these

Q9. Carbon content is highest in:
(a) Mild steel
(b) Eutectoid steels
(c) Hypoeutectoid steels
(d) Hypereutectoid steels

Q10. Which of the following is non-destructive test
(a) tensile test
(b) charpy test
(c) cupping test
(d) radiography test

S1. Ans(c)
Sol. Atoms are arranged in face centred cubic structure as all eight corners of the cube and at the centre of each face.

S2. Ans(d)
Sol. Defects in metal
(1) Point defect or zero dimensional defect
(a) Vacancy defect
(b) Interstitial defect
(c) Substitutional defect
(d) Frankle defect
(e) Schottky defect
(2) Surface defect
(a) Grain boundary defect
(b) Twin boundary defect
(c) Tilt boundary defect
(d) Staking faults
(3) Line defect
(a) Edge dislocation defect
(b) Screw dislocation defect

S3. Ans(b)
Sol. The number of electrons found in the outer most orbit of semi-conductor materials is 4.

S4. Ans(c)
Sol. Type of cell Packing factor
Simple cubic (SC) – 0.52
Hexagonal Close packed (HCP) – 0.74
Body centered cubic (BCC) – 0.68
Face-centered cubic (FCC) – 0.74

S5. Ans(b)
Sol. Annealing reduces the hardness of the steel completely and improve toughness, it is complete softening process and increase ductility.

S6. Ans(a)
Sol. Pearlite consists of 87% ferrite (layer are thick) and 13% cementite (thin layer) arranged alternatively in a lamelle formation.

S7. Ans(a)
Sol. Screw dislocation:- When a part of Crystal displaced angularly over the remaining about some edge, the dislocation is called screw dislocation.
(i) Burger’s vector is parallel to the screw dislocation line, whose direction is perpendicular.
(ii) Screw dislocation creates shear stress and strain in the crystal.

S8. Ans(b)
Sol. The atomic bond found is diamond is covalent bond.
Covalent Bond:- It is also called homopolar bond. This bond result by mutual sharing of valence electrons of identical atoms. The electronic structure of an atom is relatively stable it has eight electrons in its outer valence shell, which sometimes an atom acquires by shearing electrons with an adjacent similar atom. Diamond, methane chlorine are typical examples.

S9. Ans(d)
Sol. Carbon content is highest in hypereutectoid steels.

S10. Ans(d)
Sol. radiography test is the non-destructive test. In the radiography test there is no role of force so there is no deformation takes place within the testing material.
After the testing material is able to perform its functionality without any kind of destruction.

Quiz: Electrical Engineering 1 June 2020

Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Measurement and measuring instrument
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. Horizontally mounted moving iron instruments employ
(a) eddy current damping
(b) air friction damping
(c) fluid friction damping
(d) electromagnetic damping

Q2. The deflecting torque of moving iron instrument is
(a) I^2 dL/dθ
(b) 1/2 I^2 dL/dθ
(c) I dL/dθ
(d) 1/2 I dL/dθ

Q3. Hysteresis error, in moving iron instruments, may be reduced by using
(a) mumetal or permalloy
(b) stainless steel
(c) silver coating
(d) high speed steel

Q4. A spring controlled moving iron voltmeter draws a current of 1 mA for full scale value of 100 V. If it draws a current of 0.5 mA the meter reading is
(a) 25 V
(b) 50 V
(c) 100 V
(d) 200 V

Q5. Moving coil permanent magnet instrument can be used for the measurement of
(a) AC and DC
(b) AC only
(c) DC only
(d) half wave rectified DC

Q6. An advantage of PMMC instrument is that it
(a) is free from friction error
(b) has high torque to weight ratio of moving parts
(c) has low torque to weight ratio
(d) can be used on both AC and DC

Q7. The term artificial aging in instrument is associated with
(a) springs
(b) permanent magnets
(c) controlling torques
(d) both (a) and (b)

Q8. A PMMC voltmeter is connected across a series combination of a dc voltage source V1 = 2V and an ac voltage source V2(t)= 3 Sin (4t) volts. The meter reads
(a) 2 V
(b) 5 V
(c) (2+√3/2)V
(d) √17/2 V

Q9. Which of the following meters does not exhibit square law response?
(a) Moving coil
(b) Moving iron
(c) Electrodynamometer
(d) hot wire instrument

Q10. Which of the following instrument is commonly used to measure primary current of a transformer connected to mains?
(a) Electrostatic meter
(b) Current transformer
(c) Moving coil type meter
(d) Moving iron meter

Solutions
S1. Ans. (b)
Sol. air friction damping

S2. Ans. (b)
Sol. The correct relation for torque in moving iron is 1/2 I^2 dL/dθ.

S3. Ans. (a)
Sol. mumetal or permalloy

S4. Ans. (a)
Sol. Deflection, θ∝I^2
So, V∝I^2
V2 = V1 ((I^2 2)/(I^2 1)), putting the value in equation we get as the result
V2 = 25 V
S5. Ans. (c)
Sol. Moving coil permanent magnet instrument can be used for the measurement of DC only.

S6. Ans. (b)
Sol. has high torque to weight ratio of moving parts.

S7. Ans. (d)
Sol. Both spring and controlling torque are associated with term aging.

S8. Ans. (a)
Sol. The average value of ac current is zero so the instrument will measure 2 V .

S9. Ans. (a)
Sol. Moving iron

S10. Ans. (d)
Sol. Moving iron meter

Quiz: Mechanical Engineering 01 June 2020

Quiz: Mechanical Engineering
Exam: UPSSSC JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. The Coriolis component of acceleration of a slider moving with velocity V on a link having angular velocity ω is
(a) Vω
(b) 2 Vω
(c) 2ω/V
(d) Vω/2

Q2. Weber number is defined as the ratio of
(a) inertia force to viscous force
(b) inertia force to gravity force
(c) inertia force to surface tension force
(d) inertia force to elastic force

Q3. The ratio of RMS value to the average value of an alternating current waveform is called
(a) Peak factor
(b) Power factor
(c) Form factor
(d) None of the above

Q4. Pyrometry deals with the measurement of
(a) Elevated temperature
(b) Shocks
(c) Humidity
(d) Current

Q5. Endurance limit is associated with
(a) Torsion
(b) Bending
(c) Shear
(d) Fatigue

Q6. Reynold’s number is the ratio of
(a) Thermal conductivity to kinematic viscosity
(b) Inertia force to viscous force
(c) Heat convected to heat conducted
(d) None of these

Q7. Efficiency of Carnot cycle is (Where,T1 and T2 are the highest temperature and lowest temperature during the cycle)
(a) T1/T2 -1
(b) 1-T2/T1
(c) T1/T2 +1
(d) T1/T2

Q8. When the Mach number is less than unity, then the flow is
(a) Supersonic
(b) Sonic
(c) Subsonic
(d) None of the above

Q9. The moment of inertia of a circular section of diameter D about its diameter is________the moment of inertia about the polar axis.
(a) four times
(b) double
(c) three times
(d) half

Q10. The heat that must be absorbed by ice of mass 500g at -10 Deg C to take it to water at 20 Deg C is (specific heat of ice is 2.2 kJ/kg-K, specific heat of the water is 4.2 kJ/kg-K and latent heat of fusion of ice is 300kJ/kg)
(a) 53 kJ
(b) 243 kJ
(c) 192 kJ
(d) 203 kJ

Solutions

S1. Ans (b)
Sol. The Coriollis component of acceleration is an acceleration of slider moving with velocity V, on a rotating link with angular velocity ω.
i.e. Coriollis component of acceleration =2ωV
It acts on the slider of quick-return motion mechanism.

S2. Ans (c)
Sol. Weber number is defined as the ratio of inertia force to surface tension force. Weber number is applicable for the applications where surface tension force dominates. E.g. Capillary action in a tube etc.

S3. Ans (c)
Sol. The ratio of RMS value to the average value of an alternating current waveform is called Form factor.
R.M.S. value of alternating current is 1/√2 times of maximum amplitude of alternating current and average value of alternating current is 2/π times of maximum amplitude of alternating current.

S4. Ans (a)
Sol. Pyrometry is the branch of science which deals with the measurement of elevated temperatures. Pyrometer is such a device which is used to measure higher temperature (from 300 Deg C to 6000 Deg C)

S5. Ans (d)
Sol. Endurance limit is defined as the maximum stress/load that a component can sustain without failure when it is being subjected to cyclic loading.

S6. Ans (b)
Sol. Reynold’ s Number(Re)=(Inertia Force)/(Viscous Force)=ρVd/μ
Here,
ρ=Density of fluid
V=Average velocity of fluid
d=Diameter of conduit
μ=Dynamic viscosity of fluid

S7. Ans (b)
Sol. Efficiency of Carnot cycle (η)=1-T2/T1

S8. Ans (c)
Sol.
1. If Mach Number (Ma<1) then flow is subsonic.
2. If Mach Number (Ma=1) then flow is sonic.
3. If Mach Number (Ma>1) then flow is supersonic.
4. If Mach Number (Ma>3) then flow is hypersonic.

S9. Ans (d)
Sol.
Moment of inertia about the diameter=(πD^4)/64
Moment of inertia about polar axis=(πD^4)/32

S10. Ans (d)
Sol. Heat absorbed by ice at -10 Deg C to convert into water 20 Deg C = heat taken by ice from -10 Deg C to 0 Deg C + heat taken for phase change of ice into water at 0 Deg C + heat taken by water from 0 Deg C to 20 Deg C
=0.5×2.2×(0-(-10)+0.5×300+0.5×4.2×(20-0)
=203 kJ

Quiz Electronics Engineering 30 may 2020

Quiz Electronics Engineering

Exam: NIC

Topic: Miscellaneous

Date:  30/05/2020

 

Each Question carries 1 Mark

Negative Marking:  1/4

Time: 10 Minutes

 

 

Q1. ……. feature allows you to optimize your system and capture all possible transactions.

(a) scalability

(b) reliability

(c) elasticity

(d) None of the above

 

 

Q2. Out of given options, which one monitors user activity on internet and transmit that information in background to someone else?

(a) Trojan Horse

(b) Spyware

(c) Adware

(d) None of the above

 

 

Q3. Overlaying

(a) is transparent to the user

(b) requires use of a loader

(c) allows larger programs, but requires more effort

(d) is mostly used on large computers

 

 

Q4. What does XHTML stands for?

(a) Extra Hyperlinks and text Markup Language

(b) Extreme Hypertext Markup Language

(c) Extended Hypertext Mark Up Language

(d) Extensible Hypertext Markup language

 

 

Q5. What are SSL and TLS?

(a) Internet protocols

(b) Data Link Layer

(c) Cryptographic Protocol

(d) Internet Layer

 

 

Q6. Management of software development is dependent on

(a) People

(b) Product

(c) Process

(d) All of the above

 

 

Q7. IPv6 supports which of the following addressing modes?

(a) Unicast addressing

(b) Multicast addressing

(c) Anycast addressing

(d) All of them

 

 

Q8. _____________ enables the migration of the virtual image from one physical machine to another.

(a) visualization

(b) virtualization

(c) migration

(d) virtual transfer

 

 

Q9. Antivirus signatures are created using which of the following?

(a) Decryption Algorithm

(b) Encryption Algorithm

(c) Hashes

(d) CRC

 

 

Q10. In the relational model, cardinality is termed as:

(a) A number of attributes.

(b) A number of tuples.

(c) A number of tables.

(d) A number of constraints.

 

 

SOLUTIONS

 

S1. Ans.(c)

Sol. Elasticity is the degree to which a system is able to adapt to workload changes by provisioning and de-provisioning resources in an autonomic manner. It has the ability to right-size resources as required.

 

 

S2. Ans.(b)

Sol. Spyware is a software that is installed on your computer directly or indirectly. It monitors different programs, internet activity secretly while running in background of your computer.

 

 

S3. Ans.(a)

Sol. Overlaying is the process of transferring a block of program code or other data into internal memory, replacing what is already stored. This technique allow programs to be larger than the computer’s main memory.

 

 

S4. Ans.(d)

Sol.  Extensible Hypertext Markup Language (XHTML) is part of the family of XML markup languages.

 

 

S5. Ans.(c)

Sol.

  • Secure Sockets Layer (SSL) is a networking protocol designed for securing connections between web clients and web servers over an insecure network like internet.
  • TLS is Acronym of Transport Layer Security.

Both are cryptographic protocols designed to provide communications security over a computer network.

 

 

S6. Ans.(d)

All of the above

 

S7. Ans.(d)

Sol. IPv6 supports unicast, multicast and anycast addressing modes.

 

S8. Ans.(b)

Sol. Virtualization enables the migration of the virtual image from one physical machine to another. Virtualization allows to share a single physical instance of a resource or an application among multiple customers and organizations at one time. It helps in optimization by sharing data to different machines.

 

 

S9. Ans.(c)

Sol. An Antivirus Signature is a set of unique data or bits of code for its identification. Anti-virus software uses the virus signature to scan for the presence of malicious code.

 

 

S10. Ans.(b)

A number of tuples.

Quiz: Electrical Engineering 30 May 2020

Quiz: Electrical Engineering
Exam: NLC
Topic: Network theorems

Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. Which of the following will not be affected due to change in R?
(a) Bandwidth
(b) Q
(c) Resonant frequency
(d) None

Q2. The resonant frequency of an RLC series circuit is 1.5 MHz with the resonating capacitor of 150 pF. The bandwidth is 10 kHz. The effective value of the resistor is
(a) 16.3 Ω
(b) 9.5 Ω
(c) 7.4 Ω
(d) 4.7 Ω

Q3. A parallel circuit is said to be in resonance when the admittance is purely
(a) capacitive
(b) inductive
(c) susceptive
(d) conductive

Q4. Consider the following statement:
If a high Q parallel resonant circuit is loaded with a resistance
The circuit impedance reduces
The resonant frequency remains the same
The bandwidth reduces
Which of the above statements is/are correct?
(a) 3 only
(b) 2 only
(c) 1 only
(d) 1,2 and 3

Q5. A parallel resonant circuit can be employed
(a) as a high impedance
(b) to reject a small band of frequencies
(c) to amplify certain frequencies
(d) both (a) and (b)

Q6. What is the locus of the tip of the voltage phasor across R in a series RLC circuit?
(a) A Parabola
(b) An ellipse
(c) A circle
(d) A rectangular hyperbola

Q7. A non-ideal voltage source Vs has an internal impedance of Zs. if a purely resistive load is to be chosen that maximizes the power transferred to the load, its value must be
(a) 0
(b) real part of Zs
(c) magnitude of Zs
(d) complex conjugate of Zs

Q8. A capacitor is charged to a voltage of 440V and has a resistance of 35 ohm. Calculate the initial value of charging current.
(a) 100 A
(b) 0
(c) infinity
(d) 200 A

Q9. The total charge entering the terminal of an element is given by;
q = (6t² – 12t) mC
(a) 36 mA
(b) 24 mA
(c) 102 mA
(d) 72 mA

Q10. A load is connected to a circuit. At the terminals to which the load is connected, R_Th = 10 Ω and V_Th = 60 V. The maximum power supplied to the load is
(a) 400 W
(b) 1600 W
(c) 700 W
(d) 900 W

Solutions
S1. Ans. (c)
Sol. Frequency won’t be affected.

S2. Ans. (d)
Sol. Q =(resonance frequency)/bandwidth
=(ωr L)/R= 1/(ωr RC)
Value of R can be computed as R = 4.7 Ω
S3. Ans. (d)
Sol.
S4. Ans. (d)
Sol. All the statements are correct.
S5. Ans. (d)
Sol. A parallel resonant circuit can be employed as both of following
as a high impedance
to reject a small band of frequencies

S6. Ans. (c)
Sol. A circle

S7. Ans. (c)
Sol. magnitude of Zs

S8. Ans. (b)
Sol. Initially, there’s 0V voltage in a capacitor. As the capacitor charges, the voltage increases. Since a voltage is proportional to current by ohm’s law, initial current is also equal to zero.

S9. Ans. (a)
Sol. Sol. Current, i=dq/dt=d/dt (q)=d/dt (6t^2-12t)=(12t-12) mA
At t = 4s, i = 12 × 4 – 12 = 48 – 12 = 36 mA

S10. Ans. (d)
Sol. Under maximum power transfer, R_L-R_Th and voltage across R_L=V_Th/2.
∴P_(max.)=(V_Th/2)²/R_Th =(60/2)²/10=900 W

Quiz: Civil Engineering 30 MAY 2020

Quiz: Civil Engineering
Exam: UPSSSC-JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. According to IS 1200, the formwork shall be measured in:
(a) Tonnage
(b) cubic m
(c) square meter
(d) Linear length

Q2. The linear relation between the stress and strain of a material is valid until
(a) fracture stress
(b) elastic limit
(c) ultimate stress
(d) proportional limit

Q3. Water cement ratio is usually expressed in:
(a) Litres of water required per bag of cement
(b) Litres of water required per kg of cement
(c) m³ of water required per bag of cement
(d) m³ of water required per kg of cement

Q4. In a closed traverse……………..
(a) Difference between fore-bearing and back-bearing should be 90°
(b) Sum of included angles should be (2N-4) times right angle, where N represents the number of sides
(c) Sum of included angle should be (2N-1) time right angle, where N is the number of sides
(d) None of these

Q5. Minimum grade of concrete to be used in reinforced concrete is –
(a) M 10
(b) M 15
(c) M 20
(d) M25

Q6. Relative density of a compacted dense sand is approximately equal to
(a) 0.4
(b) 0.6
(c) 0.95
(d) 1.20

Q7. As per I.R.C. for bitumen bound macadam maximum aggregate impact value in % will be:
(a) 35
(b) 20
(c) 30
(d) 25

Q8. Aerobic attached growth process is classified under:
(a) activated sludge process
(b) chemical clarification
(c) biological treatment
(d) preliminary treatment

Q9. Dicken’s formula for determining maximum flood (with usual notation), is
(a) Q_p=CA^(3/4)
(b) Q_p=C_1 A^(2/3)
(c) Q_p=C√A
(d) Q_p=177C√A

Q10. Property of a fluid by which molecules of different kind of fluids are attracted to each other is called _________.
(a) adhesion
(b) cohesion
(c) viscosity
(d) compressibility

SOLUTIONS

S1. Ans.(c)
Sol. the formwork shall be measured in square meter.

S2. Ans.(d)
Sol. According to hooks law strain is directly proportional to stress within proportional limit.

S3. Ans.(a)
Sol. Water Cement ratio is usually expressed in liters of water required per bag of cement.
▭(water-cement ratio= (weight of water)/(weight of cement))

S4. Ans.(b)
Sol. In closed traverse, the sum of included angle should be (2n-4)×90°.
n→ No. of sides.

S5. Ans.(c)
Sol. ⇒ for Reinforced cement concrete minimum grade is M20
⇒ For plane cement concrete minimum grade is M15

S6. Ans.(c)
Sol. relative density of compacted dense sand equal to 0.95.

S7. Ans.(c)
Sol. As per I.R.C for bitumen bound macadam maximum aggregate impact value will be 30%.

S8. Ans.(c)
Sol. Aerobic attached growth process is a biological treatment in which biomass is attached over the medium and waste water passed through it.

S9. Ans.(a)
Sol. Peak flood discharge given by dicken’s formula-
Q=CA^(3/4)
Where Q= Peak flood discharge (m³/sec)
C= Dicken’s coefficient
A= Area in km²

S10. Ans.(a)
Sol. It is defined as-
Cohesion – an attractive force between same kind of fluid molecules.
Adhesion – an attractive force between different kind of fluid molecules.

Quiz Electronics Engineering 29 May 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 29/05/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. If the connection of two-port is such that the transmission matrix of the overall network is the product of the transmission matrices of the individual networks, what type of connection is it?
(a) Series Connection
(b) Parallel Connection
(c) Cascade Connection
(d) None of the above

Q2. A junction FET can be used as a Voltage Variable Resistor
(a) well below pinch-off condition
(b) beyond pinch-off voltage
(c) at pinch-off voltage
(d) for any value of V_DS

Q3. If 225_Y = 165_8, find the value of radix base.
(a) 11
(b) 8
(c) 9
(d) 7

Q4. Recursion uses more memory space than iteration because
(a) it uses stack instead of queue
(b) every recursive call has to be stored
(c) both (a) & (b)
(d) None of the above

Q5. If P(A ∩ B) = P(A)P(B), then events A and B are called
(a) independent
(b) dependent
(c) exhaustive
(d) None of the above

Q6. A balance factor in AVL tree is used to check
(a) what rotation to make
(b) if all child nodes are at same level
(c) when the last rotation occurred.
(d) if the tree is unbalanced.

Q7. In a compiler, keywords of a language are recognized during
(a) parsing of the program
(b) the code generation
(c) the lexical analysis of the program
(d) dataflow analysis

Q8. Which one of the following is not an approach to compute the Minimum spanning tree in a weighted graph?
(a) Kruskal
(b) Prim’s
(c) Boruvka’s
(d) Dijkstra’s

Q9. The addressing mode used in the instruction PUSH B is
(a) direct
(b) register
(c) register indirect
(d) immediate

Q10. Which of the following is the internal memory of the system(computer)?
(a) CPU register
(b) Cache
(c) Main memory
(d) All of the above

SOLUTIONS

S1. Ans.(c)

S2. Ans.(a)
Sol. In Triode region which is below the Pinch-off voltage the drain to source resistance is controlled by bias voltage(V_GS). Therefore, JFET can be used as Voltage Variable Resistor.

S3. Ans.(d)
Sol.
225_Y = 2 × Y^2 + 2 × Y^1 + 5 × Y^0 = 2Y^2 + 2Y^1 + 5
165_8 = 1 × 8^2 + 6 × 8^1 + 5 × 8^0 = 64 + 48 + 5 = 117
Now, 225_Y = 165_8
⇒ 2Y^2 + 2Y^1 + 5 = 117
⇒ 2Y^2 + 2Y^1 = 117 – 5 = 112
⇒ 2Y^2 + 2Y^1 – 112 = 0
So, Y = +7 & -8
Radix base cannot be negative.

Therefore, the value of radix base is 7.

S4. Ans.(c)
Sol. Recursion uses more memory compared to iteration because every time the recursive function is called, the function call is stored in stack.

S5. Ans.(a)
Sol. Two events A and B are said to be independent if the occurrence of one event has does not affect the probability that the other event will occur. If two events are independent then
P(A∩B) = P(A)P(B)

S6. Ans.(d)
Sol. AVL trees are height balancing binary search tree. It checks the difference of the height of the left and the right sub-trees and assures that it is not more than 1. This difference is called the Balance Factor. So. with the help of balance factor we check if tree is balanced or not.

S7. Ans.(c)
Sol. A keyword can also be called as Tokens. During the lexical analysis of the program a sequence of characters are converted into a sequence of tokens. Keywords are usually first recognized during lexical analysis in order to make parsing easier. Parsers are implemented by writing context-free grammars of tokens rather than of lexemes so it becomes easier to build parser after keywords are recognized.

S8. Ans.(d)
Sol. Prim’s, Kruskal’s and Boruvka’s algorithm are a Greedy algorithm. These all are used to compute the Minimum spanning tree in a weighted graph.
Prim’s Algorithm is used to find Minimum Spanning Tree (MST).
Dijkstra’s Algorithm is used to find the shortest path from source to all the other nodes in a weighted graph.

S9. Ans.(b)
Sol. In Register addressing mode, the operand is hold in the register memory mentioned in the instruction. So, In PUSH B Register addressing mode is used.

S10. Ans.(d)
Sol. All three are the internal memory of the system. CPU register is the smallest and Main memory is the largest internal memory. Registers are the smallest and the fastest memory in a computer. It hold instructions that are currently processed by the CPU.

Quiz: Mechanical Engineering 29 May 2020

Quiz: Mechanical Engineering
Exam: ISRO (TECHNICAL ASST.)
Topic: Miscellaneous

Each question carries 4 mark.
Negative marking: 1 mark
Time: 15 Minute

Q1. Chloro-fluoro carbons are banned due to
(a) High cost
(b) Toxicity
(c) High boiling point
(d) Preventing infrared rays to escape and allowing UV rays to earth

Q2. The ratio of thermal diffusivity to mass diffusivity is known as
(a) Schmidt number
(b) Sherwood number
(c) Lewis number
(d) Stanton number

Q3. A curve that is everywhere tangent to the instantaneous local velocity vector, is
(a) Streak line
(b) Path line
(c) Normal line
(d) Streamline

Q4. The tension in the cable supporting a lift is more when the lift is
(a) Moving downward with uniform velocity
(b) Moving upward with uniform velocity
(c) Moving upward with acceleration
(d) Moving downward with acceleration

Q5. When the temperature of a solid metal increases-
(a) strength of metal decreases but ductility increases
(b) both strength and ductility decrease
(c) both strength and ductility increase
(d) strength of metal increases but ductility decreases

Q6. Region of safety for maximum principal stress theory under bi-axial stress is shown by:
(a) Ellipse
(b) Square
(c) Pentagon
(d) Hexagon

Q7. When a nut is tightened by placing washer with it, the bolt will be subjected to following type of loads
(a) compression
(b) tension
(c) shear
(d) combined load

Q8. Which of the following is a statically indeterminate structure?
(a) Load supported on composite member
(b) Load supported on two members
(c) Load supported on three members
(d) Thermal load supported on two members

Q9. If steel is cooled in still air, the structure obtained is
(a) Pearlite
(b) Sorbite
(c) Troosite
(d) Acicular

Q10. Cutting power consumption in turning can be significantly reduced by
(a) increasing rake angle of the tool
(b) increasing the cutting angle of the tool
(c) widening the nose radius of the tool
(d) increasing the clearance angle

Solutions

S1. Ans (d)
Sol. Chloro-fluoro carbon has been banned due to its high ozone depletion potential as it allows UV rays to come on the earth and high global warming potential as it absorbs infrared rays coming from sun.

S2. Ans (c)
Sol. Lewis number is defined as the ratio of thermal diffusivity to mass diffusivity. It is used to characterize fluid flows where there is simultaneous heat and mass transfer.

S3. Ans (d)
Sol. A curve that is everywhere tangent to the instantaneous local velocity vector, is called stream line. The equation of streamline is,
(dx/u=dy/v=dz/w)

S4. Ans (c)
Sol. Tension in the cable will be more when the lift is moving upward with constant acceleration as compared to when the lift is moving downward.
For upward acceleration, tension (T) in the cable;
T=Mg+Ma
For downward acceleration, tension (T) in the cable;
T=Mg-Ma

S5. Ans (a)
Sol. When the temperature of a solid metal increases then strength of the metal decreases and ductility increases due to breaking in inter-molecular bonds in the metal.

S6. Ans (b)
Sol. Region of safety for maximum principal stress theory under bi-axial stress is shown by a square. Maximum principal stress theory is used for the design of brittle material.

S7. Ans (b)
Sol. When a nut with washer is tightened on a bolt then the nut is subjected to compressive stress and the bolt is subjected to tensile stress.

S8. Ans (c)
Sol. In statics and structural mechanics, a structure is statically indeterminate when the static equilibrium equations are insufficient for determining the internal forces and reactions on that structure. When load is applied on three members simultaneously then it is called statically indeterminate.

S9. Ans (b)
Sol. If steel is cooled in still air, the structure obtained is Sorbite. It is formed by rapid cooling of steel heated to above 400˚C. It is softer and more ductile than Troosite.

S10. Ans (a)
Sol. We know, according to Merchant’s theory,
∅+β-α=π/2
If α↑then ∅↑ and shear area decreases which causes to decrease in cutting force and consequently cutting power.

Quiz: Civil Engineering 29 may 2020

Quiz: Civil Engineering
Exam: UKSSSC-JE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. On horizontal curve, if the pavement is kept horizontal across the alignment, then the pressure on the outer wheels will be …………..
(a) More than the pressure under inner wheels
(b) Less than pressure under inner wheels
(c) Equal to the pressure on inner wheels
(d) Zero

Q2. Grade compensation on a horizontal curve on a highway is not necessary when:-
(a) Gradient is flatter than 4 percent
(b) Gradient is steeper than 4 percent
(c) Gradient is flatter than 6 percent
(d) Gradient is steeper than 6 percent

Q3. The shape of the camber best suited for cement concrete pavements is
(a) Straight line
(b) Parabolic
(c) Combination of straight and parabolic
(d) Circular

Q4. The ruling gradient for plain and rolling terrain is
(a) 3.3%
(b) 5%
(c) 6%
(d) 4 %

Q5. Enoscope is used to determine
(a) spot speed
(b) average speed
(c) travel time
(d) none of these

Q6. When speed of traffic flow becomes zero, then:
(a) traffic density and traffic volume both attain maximum value
(b) traffic density attains maximum value but traffic volume becomes zero
(c) Traffic density and traffic volume both becomes zero
(d) traffic density becomes zero but traffic volume attains maximum value

Q7. The pressure sustained per unit deformation of subgrade at specified deformation level using specified plate size is termed as
(a) CBR
(b) Safe bearing capacity
(c) Tangent modulus
(d) Modulus of subgrade reaction

Q8. In rigid pavements, the contraction joints spacing is normally provided as-
(a) 2.5 m
(b) 3.5 m
(c) 4.5 m
(d) 5.5 m

Q9. Standard size of wooden sleeper for broad gauge track is
(a) 180×20×11.5 cm
(b) 225×23×13 cm
(c) 250×26×12cm
(d) 274×25×13 cm

Q10. The depth of ballast D, is calculated from the following formula:
(a) D=(S-B)/2
(b) D=(S-B)/10
(c) D=(S-B)/15
(d) D=(S-B)/20

SOLUTION

S1. Ans.(a)
Sol. On a horizontal curve, if the pavement is kept horizontal across the alignment, then the pressure on the outer wheels will be more than the pressure on inner wheels.

S2. Ans.(a)
Sol. Grade compensation on a horizontal curve on a highway is not necessary when gradient is flatter than 4% .
▭(Grade compensation (%)=(30+R)/R≯75/R)

S3. Ans.(a)
Sol. Straight line camber is best suited for cement concrete pavements.

S4. Ans.(a)
Sol. The ruling gradient for plain and rolling terrain is 3.3% or 1 in 30 while for mountainous terrain it is 5% or 1 in 20.

S5. Ans.(a)
Sol. Enoscope or mirror box method is used to determine spot speed.

S6. Ans.(b)
Sol. when speed of traffic flow becomes zero, then traffic density attains maximum value but traffic volume becomes zero.

S7. Ans.(d)
Sol. The pressure sustained per unit deformation of subgrade at specified deformation level using specified plate size is termed as modulus of subgrade reaction.
▭(Moduius of subgrade reaction (K)=(pressure (P))/(Deflection (D)))
(unit = kg/m³)
It is generally calculated at 0.125 cm or 1.25 mm.

S8. Ans.(c)
Sol. Contraction joints are used to prevent the contraction in rigid pavements. The contraction joints spacing is normally provided as 4.5. m.

S9. Ans.(d)
Sol.
Gauge                              Size of sleeper
Broad Gauge                 275 × 25 × 13 cm.
Meter Gauge                 180 × 20 × 11.5 cm.
Narrow Gauge               150 × 18 × 11. 5 cm. .

S10. Ans.(a)
Sol.
▭(The depth of ballast (D) is given by=(S-B)/2)
where, S = centre to centre distance between sleepers
B =width of sleeper

Quiz Electronics Engineering 28 May 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 28/05/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The average search time of hashing, with linear probing will be less if the load factor
(a) equals one
(b) is far greater than one
(c) is far less than one
(d) none of the above

Q2. During software development, which factor is most crucial?
(a) Product
(b) Process
(c) People
(d) Project

Q3. Consider the following sorting algorithms. Which of them perform in least time in the worst case?
(a) Quick sort
(b) Heap sort
(c) Merge sort
(d) both (b) and (c)

Q4. A full binary tree with n non leaf nodes contain.
(a) log2n nodes
(b) n+1 nodes
(c) 2n+1 nodes
(d) 2n nodes

Q5. A relation scheme is in ……… if it is in the 1 NF and if all non-prime attributes are fully functionally dependent on the relation key(s).
(a) First Normal Form
(b) Second Normal Form
(c) Boyce Codd Normal Form
(d) Fourth Normal Form

Q6. Which of the following operator(s) cannot be overloaded?
(a) ?: (conditional)
(b) Size of (object size information)
(c) .*(member selection with pointer to member)
(d) All of the above

Q7. Which one of these are characteristic of RAID 5?
(a) Distributed parity
(b) Double parity
(c) Hamming code parity
(d) Dedicated party

Q8. TRUNCATE statement in SQL is a-
(a) DML statement
(b) DDL statement
(c) DCL statement
(d) All of these

Q9. A PLA can be used
(a) as a micro processor
(b) as a dynamic memory
(c) to realise a sequential logic
(d) to realise a combinational logic

Q10. Which of the following memories is directly accessible by the CPU?
(a) RAM
(b) Hard Disk
(c) Magnetic Type
(d) DVD

SOLUTIONS

S1. Ans.(c)
Sol.
Load Factor = (total number of records currently present)/(total number of records that can be present)

The average search time of hashing, with linear probing will be less if the load factor is far less than one. Load factor less than 1 is possible when free space is more. Free space more means less collision so searching time will be less.

S2. Ans.(c)
Sol. The software development is dependent upon four factors. Those are People, Product, Process and Project. Software development requires good managers. The manager who can understand the requirements of people. Hence , people are the most crucial factor during software development.

S3. Ans.(d)
Sol.
Worst case time complexity of Quick sort = O(n2,) when input is already sorted or reverse sorted.
Worst case time complexity of Heap sort = O(nlogn).
Worst case time complexity of Merge sort = O(nlogn).

S4. Ans.(c)

S5. Ans.(b)
Sol. A database is in Second Normal Form if it satisfies the following conditions:
It is in First Normal Form
All non-key attributes are fully functional dependent on the primary key

S6. Ans.(d)
Sol. Operators which cannot be overloaded are :
1. ?: (conditional)
2. .(member selection)
3. .*(member selection with pointer to member)
4. :: (scope resolution)
5. Size of (object size information)
6. typeid (object type information)

S7. Ans.(d)
Sol. RAID-5 uses disk striping with distributed parity and allow reconstruction of data when disk fails.

S8. Ans.(b)
Sol. In SQL, the TRUNCATE TABLE Command quickly deletes all data and memory allocated in a table by deallocating the data pages used by the table. It is a Data Definition Language (DDL).

S9. Ans.(d)
Sol. A Programmable Logic Array (PLA) is used to implement combinational logic circuits. It has a set of programmable AND gates, which link to a set of programmable OR gates. Those can be conditionally complemented to produce an output.

S10. Ans. (a)

Quiz: Electrical Engineering 28 May 2020

 

Quiz: Electrical Engineering

Exam: UPPSC AE

Topic: Power electronics (electrical engineering)

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

Q1. A thyristor equivalent of thyratron tube is

(a) SCR

(b) UJT

(c) Diac

(d)Traic

 

 

Q2. An SCR is considered to be a semi-controlled device because

(a) it can be turned OFF but not ON with a gate pulse

(b) it conducts only during one half cycle of an alternating current wave.

(c) It can be turned ON but not OFF with a gate pulse.

(d) It can be turned ON only during one half cycle of an alternating voltage wave

 

 

Q3. In forward bias portion of the thyristor’s i-v characteristics, the number of stable operating region is

(a) One

(b)Two

(c) Three

(d) None

 

 

Q4. Turn-on of a thyristor takes place when

(a) anode to cathode voltage is positive

(b) anode to cathode voltage is negative

(c) there is a positive current pulse at the gate

(d) the anode to cathode voltage is positive and there is a positive current pulse at the gate

 

 

Q5. In the forward blocking region of a silicon-controlled rectifier, the SCR is

(a) In the off-state

(b) In the on-state

(c) reverse biased

(d) at the point of breakdown

 

 

Q6. Once an SCR is turned on, it remains so until the anode current goes below

(a) Triggering current

(b) Breakover current

(c) Threshold current

(d) Holding current

 

 

Q7. After firing an SCR, the gate pulse is removed. The current in the SCR will

(a) remain the same

(b) immediately fall to zero

(c) rise up

(d) rise a little and then fall to zero

 

 

Q8. When a thyristor is in ON state, its gate drive be

(a) removed to save power

(b) removed or may not be removed

(c) not removed as it will turn OFF the thyristor

(d) removed to avoid increased losses and higher junction temperature

 

 

Q9. In a thyristor the minimum current required to maintain the device in the ON state is called

(a) latching current

(b) ignition current

(c) holding current

(d) Avalanche current

 

 

Q10. In a thyristor the relation between the Holding current and latching current,

(a) more than latching current

(b) less than latching current

(c) equal to latching current

(d) equal to zero

 

Solutions

S1. Ans. (a)

Sol. SCR

 

S2. Ans. (c)

Sol. It can be turned ON but not OFF with a gate pulse.

 

S3. Ans. (b)

Sol. Two

 

S4. Ans. (d)

Sol. Turn-on of a thyristor takes place when the anode to cathode voltage is positive and there is a positive current pulse at the gate.

 

S5. Ans. (a)

Sol. In the forward blocking region of a silicon-controlled rectifier, the SCR is in the off-state.

 

S6. Ans. (d)

Sol. Once an SCR is turned on, it remains so until the anode current goes below Holding current.

 

S7. Ans. (a)

Sol. After firing an SCR, the gate pulse is removed. The current in the SCR will remain the same.

 

S8. Ans. (d)

Sol. removed to avoid increased losses and higher junction temperature

 

S9. Ans. (c)

Sol. Holding current

 

S10. Ans. (b)

Sol. less than latching current (IL)

 

 

Quiz:Mechanical Engineering 28 May 2020

Quiz: Mechanical Engineering
Exam: UPPSC AE
Topic: Miscellaneous

Each question carries 3 mark.
Negative marking: 1 mark
Time: 10 Minute

Q1. When an impeller has backward curved vanes in a centrifugal blower, then with an increase in flow rate, Euler head H
(a) increases
(b) decreases
(c) remains constant
(d) none of the above

Q2. C.I. engine as compared to S.I. engine require
(a) No flywheel
(b) Same size flywheel
(c) Smaller flywheel
(d) Bigger flywheel

Q3. The leakage in a refrigeration system using ammonia is detected by
(a) Halide torch
(b) Sulphur sticks
(c) Soap solution
(d) Hot water

Q4. A steam pipe is to be insulated by two insulating materials put over each other. For best results
(a) Better insulation should be put over pipe and inferior one over it.
(b) Inferior insulation should be put over pipe and better one over it
(c) Both may be put in any order
(d) Whether to put inferior one over pipe or the better one would depend on steam temperature

Q5. Consider the following phenomenon
1.Boiling
2.Free convection in air
3.Forced convection
4.Conduction in air
There correct sequence in the increasing order of heat transfer is
(a) 4, 2, 3, 1
(b) 1, 2, 3,4
(c) 4, 3, 2, 1
(d) 3, 4, 2, 1

Q6. Newton’s law of viscosity is about
(a) Ideal fluid
(b) Velocity gradient and rate of shear strain relation
(c) Shear deformation and shear stress relation
(d) Pressure and volumetric strain

Q7. The parameters which determine the friction factor for turbulent flow in a rough pipe are:
(a) Froud number and relative roughness
(b) Froud number and Mach number
(c) Reynolds number and relative roughness
(d) Mach number and relative roughness

Q8. A body of mass 20 kg is lifted up through a height of 4 m. How much work is done? (take g = 9.81 m/s^2)
(a) 648 J
(b) 684 J
(c) 748 J
(d) 784 J

Q9. Stress concentration occurs when:
(a) a body is subjected to excessive stress
(b) a body is subjected to unidirectional stress
(c) a body is subjected to fluctuating stress
(d) a body is subjected to non-uniform stress distribution

Q10. For a single row angular contact ball bearing, the basic dynamic capacity is 55 kN and the dynamic equivalent load is 3950 N. The rated life of the bearing is:
(a) 2700 million revolutions
(b) 2200 million revolutions
(c) 1700 million revolutions
(d) 1200 million revolutions

Solutions

S1. Ans.(b)
Sol. When we increase flow rate in a backward curved vane centrifugal compressor then Euler head decreases.

S2. Ans.(d)
Sol. C.I. engine as compared to S.I. engine requires bigger flywheel because of large torque carrying capacity of C.I. engine.

S3. Ans.(b)
Sol. Leakage in refrigeration system is detected by using sulphur sticks. Pass the stick over and around the area where you suspect the ammonia leak. If the sulphur stick begins to emit white smoke, this indicates the presence of ammonia.

S4. Ans.(a)
Sol. Better insulation should be put on the pipe to avoid any heat transfer from pipe and inferior one has to be put on above the better insulation for efficient insulation of the pipe.

S5. Ans.(a)
Sol. Correct sequence of increasing order of heat transfer is
Conduction in air < Free convection < Forced convection < Boiling

S6. Ans.(c)
Sol. Newton’s law of viscosity shows the relation between Shear stress and rate of shear strain. i.e. τ=μ du/dy.
τ=shear stress
du/dy=Rate of shear strain

S7. Ans.(c)
Sol. Friction factor for Turbulent flow is a function of Reynolds number and relative roughness. But for laminar flow, it is only a function of Reynolds number.

S8. Ans.(d)
Sol. Work done to lift a mass of 20 kg up to 4 m
W = force × distance
W = m×g×h
W = 20×9.81×4
W = 784.8 N-m or 784.8 J

S9. Ans.(d)
Sol. Stress concentration occurs when there is sudden change in the geometry of the object. It may be due to cracks, sharp corners, holes etc. All of these creates non-uniform stress distribution.

S10. Ans.(a)
Sol. Given,
Basic dynamic capacity = 55 kN
Dynamic equivalent load = 3950 N
For ball bearing, n = 3
Life=((Dynamic capacity)/(Dynamic equivalent load))^n
=(55000/3950)^3
=2699.8 or 2700 million revolutions

Quiz: Electrical Engineering 27 May 2020

Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Network theorems
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. Eight cells each of e.m.f. E and internal resistance r are connected in series. If due to oversight, two cells are connected wrongly, then equivalent e.m.f. and internal resistance of the combination are:
(a) 10 E and 6r
(b) 6 E and 10r
(c) E and 3r
(d) 4E and 8r

 

Q2. An ammeter has a resistance of 60 Ω and requires 10 mA for full-scale deflection. The shunt resistance S required to allow the meter to measure currents up to 100 mA is
(a) 5.56 Ω
(b) 2.5 Ω
(c) 6.67 Ω
(d) 8.75 Ω

 

Q3. Two resistors of resistances 6 Ω and 9 Ω are connected in parallel. The power dissipated in 6 Ω resistor is 15 W. The power dissipated is 9 Ω resistor is
(a) 10 W
(b) 24 W
(c) 6 W
(d) 16 W

 

Q4. Three capacitors of capacitance 12 μ F each are available. The minimum and maximum capacitances which may be obtained are
(a) 8 μ F, 24 μ F
(b) 4 μ F, 36 μ F
(c) 6 μ F, 33 μ F
(d) none of above

 

Q5. The desired voltage regulation for a single phase, 50 Hz transformer is zero. Its pu ohmic drop is 4% and pu reactive drop is 4%. The required power factor angle for the operation in degrees
a) 600
b) 900
c) 300
d) 450

 

Q6. For a separately excited dc machine of 25 kW, 250 V and armature resistance of 0.25 ohms, is running at 3000 rpm with supply of 255 V.
The electromagnetic power produced at the armature in kilo watts is
a) 0.5
b) 10
c) 5
d) 8

 

Q7. An alternator is to be used for generation purpose in an aircraft. The most suited operating frequency of the alternator should be
a) of 400 Hz to remove extra bulk
b) of 400 Hz to reduce losses
c) of 50 Hz to remove extra bulk
d) none of the mentioned

 

Q8. A 3-phase synchronous alternator is connected to the infinite bus is over excited, which corresponds to
a) inductor
b) capacitor
c) variable inductor
d) any of the mentioned

 

Q9. Separately excited dc generators are used in
a) Ward Leonard system of speed control
b) Hopkinson’s testing
c) Voltage control
d) None of the mentioned

 

Q10. Maximum torque in dc series motor is limited by
a) commutation
b) heating
c) field control
d) all of the mentioned

Solution

S1. (d)
Equivalent e.m.f. = E + E + E + E + E+ E – E – E=4E
Internal resistance = r+ r + r + r + r + r +r + r = 8r

S2. (c)
Full-scale voltage across meter = IR=10 mA×60 Ω=0.6 V. When circuit current is 100 mA, current through shunt = 100 – 10 = 90 mA.
∴ S=(0.6 V)/(90 mA)=6.67 Ω
S3. (a)
P=V^2/R or V=√(PR.) Since voltage is same in a parallel circuit, P_1 R_1=P_2 R_2 or 6×15 = P_2×9
∴P_2=10 W

S4. (b)
The capacitance is minimum when the three capacitors are connected in series and maximum when connected in parallel. i.e. 4 μ F and 36 μ F.

S5. (d)
Sol. The power factor angle is, tan (φ)=pu resistive drop/pu reactive drop
= 4/4= 1
tan^(-1)⁡1= 45°
S6. (c)
Sol. The current in armature, Ia = 255-250/0.25 = 20 A
Power = Eb*Ia = 250*20 = 5000 W
S7. (a)
Sol. The components to be used in aircrafts are made to operate at very high frequencies so that the size of the components to be used is reduced.
S8. (b)
Sol. In the mentioned condition the generator will correspondence as capacitor.
S9. (a)
Sol. Separately excited dc generators are used in Ward Leonard system of speed control.

S10. (a)
Sol. Commutation is the process which reduces the induced emf and so the torque.

Quiz Electronics Engineering 26 May 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 26/05/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. A problem in mathematics is given to three students whose chances of solving it are respectively 1/2, 1/3 and 1/4. The probability that the problem will be solved is:
(a) 1/2
(b) 1/4
(c) 7/12
(d) 3/4

Q2. Which of the following applications include a phase-locked loop (PLL) circuit?
(a) Modems
(b) AM decoders
(c) Tracking filters
(d) All of these

Q3. The number of independent loops for a network with n nodes and b branch is
(a) n – 1
(b) b – n
(c) b – n + 1
(d) independent of the number of nodes

Q4. The number of station accommodated in a 100kHz bandwidth with highest modulating frequency of 5 kHz is
(a) 5
(b) 10
(c) 15
(c) 20

Q5. Compiler can diagnose
(a) grammatical errors only
(b) logical errors only
(c) grammatical as well as logical errors

Q6. The register which holds the address of the location to or from which data are to be transferred is called
(a) index register
(b) instruction register
(c) memory address register
(d) memory data register

Q7. In a binary max heap containing ‘n’ numbers, the smallest element can be found in time
(a) O(n)
(b) O(logn)
(c) O(log(logn))
(d) O(1)

Q8. The main difference between the operation of transmission lines and waveguides is that
(a) the latter are not distributed, like transmission lines
(b) the former can use stubs and quarter-wave transformers, unlike the latter
(c) transmission lines use the principal mode of propagation, and therefore do not suffer from low-frequency cut-off
(d) terms such as impedance matching and standing-wave ration cannot be applied to waveguides.

Q9. Which of the following circuit can be used as parallel to serial converter?
(a) Multiplexer
(b) Demultiplexer
(c) Decoder
(d) Digital Counter

Q10. To sort many large objects or structures, it would be most efficient to
(a) place reference to them in an array and sort the array
(b) place them in a linked list and sort the linked list
(c) place pointers to them in an array and sort the array
(d) place them in an array and sort the array

SOLUTIONS

S1. Ans.(d)
Sol. Given:
Probability of problem solved by first student is P(A) = 1/2
Probability of problem solved by second student is P(B) = 1/3
Probability of problem solved by third student is P(B) = 1/4

Finding probability of problem not solved in each case,
P’(A) = 1 – 1/2 = 1/2
P’(B) = 1 – 1/3 = 2/3
P’(C) = 1 – 1/4 = 3/4

Now, Probability of none of them solved the problem correctly is
P’(A) P’(B) P’(C) = 1/2 × 2/3 × 3/4 = 1/4

So, Probability of problem being solved is
⇒ P(A) P(B) P(C) = 1 – P’(A) P’(B) P’(C)
⇒ P(A) P(B) P(C) = 1 – 1/4 = 3/4

Therefore, The probability that the problem will be solved is 3/4 .

S2. Ans.(d)

S3. Ans.(c)
Sol.
No. of independent loop = b + n – 1
No. of Loop Equation = b – n + 1
No of independent of node = n – 1

S4. Ans.(b)
Sol. Given:
The highest modulating frequency = 5kHz
Bandwidth = 100 kHz

Let number of stations accommodated be ‘n’.

Now, n × 2 × 5 = 100
⇒ 10n = 100
So, n = 10

S5. Ans.(a)

S6. Ans.(c)
Sol. Memory Address Register (MAR) either stores the memory address from which data will be fetched from the CPU, or the address to which data will be sent for storage.

S7. Ans.(a)
Sol. The smallest element in a max heap is always present at a leaf node. As Heap is a complete binary tree and every complete binary tree contain up to n/2 nodes on leaf. So, to examine all of them we would need O(n) time.

S8. Ans.(c)

S9. Ans.(a)
Sol. Multiplexer has many inputs and one output so it is also called “Parallel to Serial Converter” or “Data Selector”.

S10. Ans.(b)
Sol. Linked list is most efficient because –
Insertion and Deletion is easy for rearranging of elements .
Memory is allocated at run-time.
consists of multiple data type.
proper utilization of memory.

Quiz: Mechanical Engineering 26 May 2020

Quiz: Mechanical Engineering
Exam: ISRO TECHNICAL ASSISTANT
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/3 mark
Time: 10 Minutes

Q1. Autofrettage is a method of
(a) joining thick cylinders
(b) Reliving stresses from thick cylinders
(c) Prestressing thick cylinders
(d) Increasing the life of thick cylinders

Q2. In circular arc cam with a flat faced reciprocating follower, the contact between the
follower and the nose of cam is only maintained if :
(a) External spring force is less than the inertia force of the follower
(b) External spring force is greater than the inertia force of the follower
(c) External spring force is zero
(d) The inertia force is more than the spring force

Q3. A governor is said to be isochronous when the equilibrium speed is
(a) variable for different radii of rotation of governor balls
(b) constant for all radii of rotation of the balls within the working range
(c) constant for particular radii of rotation of governor balls
(d) constant for only one radius of rotation of governor balls

Q4. The effect of increasing the stiffness of springs of centrifugal clutch is
(a) The decrease of engagement speed
(b) The increase of engagement speed
(c) The increase of frictional force at maximum speed
(d) None of the above

Q5. The saturation temperature of steam with increase in pressure increase
(a) linearly
(b) rapidly first and then slowly
(c) slowly first and then rapidly
(d) inversely

Q6. Carbonization of coal is the process of
(a) pulverizing coal in inert atmosphere
(b) heating wood in a limited supply of air at temperatures below 300°C
(c) strongly heating coal continuously for about 48 hours in the absence of air in a
closed vessel
(d) binding the pulverized coal into brackets

Q7. Superheating of steam is done at
(a) constant volume
(b) constant temperature
(c) constant pressure
(d) constant entropy

Q8. Fluid is a substance that
(a) cannot be subjected to shear forces
(b) always expands until it fills any container
(c) has the same shear stress at a point regardless of its motion
(d) cannot remain at rest under action of any shear force.

Q9. Match List-I with List-II and select the correct answer using the code given below the lists:
List – I
Heat exchangers
Turbulent flow
Free convection
Radiation heat transfer
List–II
View factor
Effectiveness
Nusselt number
Eddy diffusivity
Codes
A B C D
(a) 3 1 2 4
(b) 2 4 3 1
(c) 3 4 2 1
(d) 2 1 3 4

Q10. Specific speed of a fluid machine
(a) refers to the speed of a machine of unit dimensions
(b) is a type-number representative of its performance
(c) is specific to the particular machine
(d) depends only upon the head under which the machine operates

SOLUTIONS

S1. Ans.(c)
Sol. Autofrettage: It is one of the oldest methods of prestressing (method of increasing pressure capacity) the cylinders. It is overloading the cylinder before it is put into service. In this method, a forged cylinder is subjected to a large internal pressure, so as to expand the internal diameter, causing overstrain. The internal pressure is applied is such a way that a portion of the cylinder at the inner surface is subjected to stresses in the plastic range. When the pressure is released, the portion of the cylinder at the outer surface contracts exerting the pressure on the portion at the inner surface which has undergone permanent deformation. As a result residual compressive stresses are induced at the inner surface and tensile stresses at the outer surface.
It is commonly used to gun barrels. It not only increases the pressure capacity of the cylinder, but also improves the endurance strength.

S2. Ans.(b)
Sol. When the cam contact force goes to zero, the cam and follower will separate. Large enough spring force is necessary to keep cam and follower in contact throughout the entire rotation. External spring force should be greater than inertia force of the follower to maintain positive contact. If external spring force is too large, there is possibility of higher contact stress leading to surface failure.

S3. Ans.(b)
Sol. Isochronous governor is a governor that keeps the speed of a prime mover constant at all loads. Also known as a static governor. A governor is said to be isochronous if equilibrium speed is constant for all the radii of rotation in the working range. Therefore, for an isochronous governor the speed range is zero and this type of governor shall maintain constant speed.

S4. Ans.(b)
Sol. When the load is released from clutch lever, it again engages with the shaft. As the stiffness of spring will increases, the restoring force on clutch will increase and hence velocity of engagement will be more.

S5. Ans (b)
Sol. At atmospheric pressure the saturation temperature is 100°C. However, if the pressure is increased, this will allow the addition of more heat and an increase in temperature without a change of phase. Therefore, increasing the pressure effectively increases both the enthalpy of water, and the saturation temperature.

S6. Ans (c)
Sol. Coal carbonization is used for processing of coal to produce coke using metallurgical grade coal. Coal carbonization involves heating of coal in the absence of air.

S7. Ans (c)
Sol. Superheated steam is a steam at a temperature higher than its vaporization (boiling) point at the absolute pressure where the temperature is measured

S8. Ans (d)
Sol. A fluid is a substance that continuously deforms under an applied shear force.

S9. Ans.(b)
Sol.
(a) Heat exchangers : Effectiveness
(b) Turbulent flow : Eddy diffusivity
(c) Free convection : Nusselt number
(d) Radiation heat transfer : View factor

S10. Ans (b)
Sol. Specific speed is of a fluid machine is a type number representative of its performance.
In order to compare the performance of different pumps, it is necessary to have some term which will be common to all the centrifugal pump the term ordinarily used for this purpose is the specific speed. This is a type characteristic and can be used to predict the behavior of one pump based on tests of similar, but different sized pumps.
The specific speed is a characteristic of pumps which can be used as basis for comparison of the performance of different pump.

Quiz: Electrical Engineering 25 May 2020

Quiz: Electrical Engineering

Exam: UPSSSC JE

Topic: Utilization of electrical energy

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

 

Q1. Air is dehumidified

(a) cooling

(b) chemical absorption

(c) heating

(d) both (a) and (b)

 

 

Q2. The conditions conductive to comfort depends upon

(a) humidity

(b) temperature

(c) air purity

(d) All of above

 

 

Q3. The speed of steam locomotive is controlled by

(a) applying breaks

(b) gear box

(c) regulating steam flow to engine

(d)  flywheel

 

 

Q4. The pulsating torque exerted by steam locomotive causes

(a) jolting and skidding

(b) hammer blow

(c) pitching

(d) all of the above

 

 

Q5. Steam engine drive

(a) has limited overload capacity

(b) is not clean drive

(c) is not suitable for urban or suburban service or for hauling heavy loads on steep gradients

(d) all of the above

 

 

Q6. Steam locomotive

(a) cannot be put into service at any moment

(b) cause considerable wear on the track

(c) need more repair and maintenance

(d) all of the above

 

 

Q7. Steam engine drive is not suitable for urban and suburban services as

(a) it is not clean drive

(b) coefficient of adhesion of steam locomotives is quite low

(c) steam locomotive cause considerable wear on the track

(d) steam locomotive has limited speed

 

 

Q8. Battery driven vehicles

(a) are easy to control and very convenient to use

(b) have low maintenance cost

(c) cause no pollution

(d) all of the above

 

 

Q9. Main traction systems used in India are those using

(a) steam engine locomotive

(b) diesel engine locomotive

(c) diesel electric locomotive

(d) All of the above

 

 

Q10. Battery operated trucks are used

(a) in power station

(b) for local delivery of goods in large town within maximum daily run up to 50-60 km

(c) in narrow gauge traction

(d) for main line service

 

 

Solutions

S1. Ans. (b)

Sol. Both cooling and chemical absorption are used to dehumidify.

S2. Ans. (d)

Sol. All factors are important.

S3. Ans. (c)

Sol. The speed of steam locomotive is controlled by regulating steam flow to engine.

S4. Ans. (a)

Sol. The pulsating torque exerted by steam locomotive causes jolting and skidding.

 

S5. Ans. (d)

Sol. All factors are true for steam engine

S6. Ans. (d)

Sol.  Feature of Steam locomotive

  • cannot be put into service at any moment
  • cause considerable wear on the track
  • need more repair and maintenance

 

S7. Ans. (b)

Sol. Steam engine drive is not suitable for urban and suburban services as coefficient of adhesion of steam locomotives is quite low .

 

S8. Ans. (d)

Sol. Benefits of Battery driven vehicles

  • are easy to control and very convenient to use
  • have low maintenance cost
  • cause no pollution

 

S9. Ans. (d)

Sol. All locomotives are used in main traction system.

S10. Ans. (b)

Sol. Battery operated trucks are suitable for local delivery of goods in large town within maximum daily run up to 50-60 km.