WBSETCL Junior Engineer Electrical Grade II 14th March 2022 First Shift Solution PDF
Question : 1
A room of 12 m length and 10 m breadth is lighted by 15 lamps to a fairly uniform illumination of 100 Im/m2. Calculate the utilisation coefficient of the room given that the output of each lamp is 1600 lumens.
Given A = 12 m × 10 m
Total lamps = 15 lamps
Each lamp output = 1600 lumens
Illumination E = 100 lm/m2
Total lumens reaching the working plane = 100 × 12 × 10 =12000 lumen
Total lumen emitting from source = 1600 × 15 = 24000 lumen
Utilization Coefficient=total lumens reaching the working plane/total lumens emitting from source
Utilization Coefficient=12000/24000 = 0.5 or 50%
Question : 2
What will the below syntax do in C programming language?
scanf (“%6s””, str1);
The scanf function is the “opposite” of printf. Whereas printf produces output on the screen, scanf reads from the keyboard.
scanf (“%6s””, str1);
So scanf read a string of maximum 6 characters from the beginning.
Question : 3
If the two glass sheets used to sandwich the thin layer of a liquid crystal are deposited with transparent electrodes on their inside faces in a liquid crystal cell, then it is known as a __________
A liquid crystal cell (LCD) consists of a thin layer (about 10 u m) of a liquid crystal sandwiched between two glass sheets with transparent electrodes deposited on their inside faces.
If both glass sheets are transparent then the cell is known as transmittive type cell.
Question : 4
Excitation in an electrical machine means production of magnetic flux by passing current in the field winding.
In order to excite the field winding on the rotor of the synchronous machine the direct current is required.
Question : 5
A commutator consists of a set of copper segments which are insulated from each other. How is the number of segments determined?
The purpose of the commutator is to rectify the ac waveform.
The segments of the commutator are insulated from each other and the armature shaft.
To help produce a smoother dc output, more coils and commutator segments are used.
The coils are insulated from each other, the same as the commutator segments.
The number of commutator segments is equal to the number of slots or coils.
Question : 6
How much load is applied for about one minute to each of the insulator during proof load test of insulator?
Proof Load Test of Insulator
In proof load test of insulator, a load of 20% in excess of specified maximum working load is applied for about one minute to each of the insulator.
Question : 7
What is the primary task of the technical department of an organisation?
Quality control is a process by which a business ensures that product quality is maintained or improved.
To enhance the quality of finished goods is the primary task of the technical department of an organisation.
Question : 8
How many elements are joined to a principal node?
There are two types of nodes
Simple node-A simple node connect 2 elements.
Principal node-It connect more than 2 elements.
Question : 9
According to which method, a network can enumerate many sequences of activities from starting event to end event?
The Critical Path Method (CPM) is one of the most important concepts in project management, and certainly among the most enduring.
The critical path method (CPM) is also known as critical path analysis (CPA).
It is a scheduling procedure that uses a network diagram to depict a project and the sequences of tasks required to complete it, which are known as paths.
The continuous strings of critical activities in the schedule between the Start and Finish of the project.
Question : 10
Find the force (F in Newton) between two point-source charges (Q1 and Q2) in Coulomb) in air when the distance between the charges is d in metre.
Coulomb’s law-It states that the magnitude of the electrostatic force F between two point charges D1 and D2 is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance d between them.
Question : 11
Which of the following instruments is used to measure the air gap between the rotor and stator of the starter motor?
A feeler gauge is a tool used to measure gap widths.
They consist of a number of small lengths of steel of different thicknesses with measurements marked on each piece.
Feeler gauge is used to measure the air gap between the rotor and stator of the starter motor.
Question : 12
What happens to the diversity factor in the case of an interconnected Grid System?
Interconnected grid system-The connection of several generating stations in parallel is known as interconnected grid system.
Interconnected grid Advantages
1.Exchange of peak loads.
2.Ensures economical operation.
3.Increases diversity factor.
4.Reduces plant reserve capacity.
The grid system can improve the diversity factor of each generating station connected to the grid. The diversity factor gets improved because the maximum demand of the grid shared by the generating station is much lesser than the maximum demand imposed on the generating station if it runs individually.
Question : 13
A heavily doped semiconductor diode which is designed to operate in reverse direction is known as the Zener diode.
The diode which is specially designed for optimising the breakdown region is known as the Zener diode.
The symbolic representation of Zener diode is shown in the figure below.
Question : 14
Which of the following instruments measure the wind speed and passes the speed information to PLC to control the turbine power in a wind power plant?
Major Parts of Wind Turbine
Anemometer-It measures the wind speed and passes the speed information to PLC to control the turbine power.
Turbine Controller-Turbine controller is a computer (PLC) that controls the entire turbine. It starts and stops the turbine and runs self diagnostic in case of any error in the turbine.
Wind Vane-It senses the direction of the wind and passes the direction to PLC then PLC faces the blades in such a way that it cuts the maximum wind.
Pitch drive motors control the angle of blades whenever the wind changes it rotates the angle of blades to cut the maximum wind, which is called pitching of blades.
Yaw Drive-Blades and other components in wind turbine are housed in a nacelle, whenever any change in wind direction is there, the nacelle has to face in the direction of the wind to extract the maximum energy from wind. For this purpose yaw drive, a motor is used to rotate the nacelle. It is controlled by PLC that uses the wind vane information to sense the wind direction.
Question : 15
Which of the following can be used as a moderator in nuclear power plants?
Nuclear Reactor-A nuclear reactor is a system that contains and controls sustained nuclear chain reactions.
Neutron Moderators-A Neutron moderator is a medium that reduces the speed of fast neutrons i.e., nuclear chain reaction. Moderators are like accelerators.
Commonly used moderators
1.Regular light water
Question : 16
Which of the following characteristics is NOT desirable for the DC amplifier?
DC amplifier-ADC amplifier (direct coupled amplifier) can be defined as is a kind of amplifier where the one stage output of the amplifier can be connected to the next stage input for allowing the signals without frequency.
Desirable characteristics for the DC amplifier
A. Good thermal and long term stability
B. Balanced differential inputs
C. High common mode rejection ratio
D. High input impedance
Common Mode Rejection Ratio-The ratio of the change to the output voltage with regards to the change in the common mode input voltage is called the Common Mode Rejection Ratio or CMRR.
Question : 17
Which of the following is NOT true for a hydroelectric power plant?
A hydroelectric power station consists of turbines that rely on a gravity flow of water from the dam to turn a turbine to generate electricity.
No fuel requirement, low running cost, Neat and clean source of energy and no standby losses are advantages of hydroelectric power plants.
Due to low maintenance cost and no fuel requirement running cost & cost of transmission of a plant is very low.
Question : 18
What are the four Sections of the total memory in PLC?
PLC-Programmable Logic Controller (PLC) is a digital computer used for the automation of various electro-mechanical processes in industries.
The memory is the area of the CPU in which data and information is stored and retrieved.
The total memory area can be subdivided into the following four Sections.
1. I/O Image Memory
The input image memory consists of memory locations used to hold the ON or OFF states of each input field devices, in the input status file.
The output status file consists of memory locations that stores the ON or OFF states of hardware output devices in the field.
Data is stored in the output status file as a result of solving user program and is waiting to be transferred to the output module’s switching device.
2. Data Memory
It is used to store numerical data required in math calculation, bar code data etc.
3. User Memory
It contains user’s application program.
4. Executive Memory
It is used to store an executive program or system software. An operating system of the PLC is a special program that controls the action of CPU and consequently the execution of the user’s program.
Question : 19
What is the function of the shunt reactor in a substation?
Shunt reactors provide voltage control and reactive power compensation.
They are arranged between line voltage and ground.
Their place of installation is usually located at the start or end of a long overhead power line or cable connection, or in central substations.
Question : 20
Which of the following is true for the earth wire?
Earth wire protects us from electrical shocks.
Earthing is referred to as the process of transfer of charge of a body to the earth.
It protects us from electric shocks due to any electrical leakages.
Question : 21
Which of the following term is a synonymous term to industrial management?
Industrial Engineering is an engineering profession that is concerned with the optimization of complex processes, systems, or organizations by developing, improving and implementing integrated systems of people, money, knowledge, information and equipment.
Industrial engineering term is a synonymous term to industrial management.
Question : 22
Which Type of Lightning Arrester consists of a divided spark gap in series with a resistance element having non-linear characteristics?
The lightning arrester protects the electrical equipment from lightning. It is placed very near to the equipment and when the lightning occurs the arrester diverts the high voltage wave of lightning to the ground.
The lightning arrestor is mainly classified into twelve types. These types are
- Road Gap Arrester
- Sphere Gap Arrester
- Horn Gap Arrester
- Multiple-Gap Arrester
- Impulse Protective Gap
- Electrolytic Arrester
- Expulsion Type Lightning Arrester
- Valve Type Lightning Arresters
- Thyrite Lightning Arrester
- Auto valve Arrester
- Oxide Film Arrester
- Metal Oxide Lightning Arresters
Valve Type Lightning Arrester
Such type of resistor is called nonlinear diverter.
It essentially consists a divided spark gap in series with a resistance element having the nonlinear characteristic.
Question : 23
Which of the following is NOT one of the addressing modes in 8085 Microprocessor?
The way of specifying data to be operated by an instruction is called addressing mode.In 8085 microprocessor there are 5 types of addressing modes
i) Immediate addressing
ii) Register addressing
iii) Direct addressing mode
iv) Register indirect addressing mode
v) Implied/Implicit addressing mode
Question : 24
A 40 KVA, single phase transformer has 400 turns on the primary and 100 turns on the secondary. The primary is connected to 2220 V, 50 Hz supply. Determine the maximum value of flux.
E1 = 4.44 f N1 ϕm
f = frequency
N = Number of turns
ϕm = flux
2220 = 4.44 × 50 × 400 × ϕm
Question : 25
Two capacitors having capacitance of 6 µfd and 10 µfd, respectively, are connected in series across a 320 V supply. Find the P.D. across the 6 µfd capacitor.
V6=V × C2/(C1+C2)
V6=320 × 10/(6+10)
Question : 26
What should be the insulation resistance of the HV side of the 1600 kVA, 20 kV/400 V three-phase transformer at 30° C?
3 Phase Transformer (Star) IR Value (MΩ) = C X E (P-n) / (√KVA)
Where C= 1.5 for Oil filled T/C with Oil Tank, 30 for Oil filled T/C without Oil Tank or Dry Type T/C.
IR Value at HV Side= (1.5 x 20000) / √ 1600 =16000 / 40 = 750 MΩ at 20⁰C
Temperature correction Factor AT 30⁰C= 1.98
So 750 MΩ×1.98=1485MΩ
Question : 27
What types of the enclosure is used for the motors used for chemical works, flour and cement works?
The enclosure is a part of the motor used for the protection from environment.
Some of the principle types of enclosures are us follows
1.Screen protected- General purpose type for used in workshop.
2. Drip proof- Used wherever there is a possibility of water dripping or spraying over the motor such as in the basement of power houses, outdoor plants like gantry cranes etc.
3. Pipe-ventilated- Chemical works, flour and cement works, etc.
4. Forced Draught- Where natural ventilation by the fan provided on the armature shaft will not be sufficient, such as in case of slow speed machines, and traction motors, etc.
5. Totally enclosed- Where admission of air from outside is not permissible, such as in boiler rooms, steel works, foundries, outdoor electrical installations, winches and cranes exposed to the weather, etc.
6. Flame proof- Where the motor has to work in explosive atmosphere, as in gas works, oil plants, coal mines, etc.
Question : 28
Lissajous figure is the pattern which is displayed on the screen, when sinusoidal signals are applied to both horizontal & vertical deflection plates of CRO.
These patterns will vary based on the amplitudes, frequencies and phase differences of the sinusoidal signals, which are applied to both horizontal & vertical deflection plates of CRO.
1.If the Lissajous figure is a straight line with an inclination of 45∘ with positive x-axis, then the phase difference between the two sinusoidal signals will be 0∘. That means, there is no phase difference between those two sinusoidal signals.
2.If the Lissajous figure is a straight line with an inclination of 135∘ with positive x-axis, then the phase difference between the two sinusoidal signals will be 180∘. That means, those two sinusoidal signals are out of phase.
3. If the Lissajous figure is in circular shape, then the phase difference between the two sinusoidal signals will be 90∘ or 270∘.
4. If the Lissajous figure is in elliptical shape, then the phase difference between the two sinusoidal signals will be 30∘ or 330∘.
Question : 29
Which of the following is NOT true for the salient pole rotor when compared to the cylindrical rotor?
Salient pole type of rotor-Salient pole type of rotor consist of large number of projected poles (salient poles) mounted on a magnetic wheel. They are larger in diameter and smaller in axial length.
Salient pole rotors are used in low-speed devices, from 100 rpm to 1500 rpm.Non-salient pole type rotors-Non-salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings. They are smaller in diameter but having a longer axial length.
Non-salient pole type rotors are used in high-speed alternators having speed between 1500 rpm to 3000 rpm.
Comparison between Salient pole type of rotor & Non-salient pole type rotors
|Salient pole rotor||Cylindrical rotor|
|Large diameter and short axial length||Small diameter and long axial length|
|used for low-speed alternators||Used for high-speed turbo alternators|
|Has no projecting poles||Has no projecting poles|
|Needs damper windings||Do not need damper windings|
|Windage loss is more||Windage loss is less|
Question : 30
What should be the length of the span for the centenary wire on a single route in traction?
The span of catenary wire may be from 45 to 90 metres with a sag of from 1 to 2 metres respectively for straight track.
Question : 31
A coil of copper wire 200 m long and of cross sectional 0.8mm2 has a resistivity of 0.02 μΩ m at normal working temperature. Calculate the resistance of the coil.
Question : 32
Transducer using Hall effect converts ___________.
The hall effect element is a type of transducer used for measuring the magnetic field by converting it into an emf.
The direct measurement of the magnetic field is not possible. Thus the Hall Effect Transducer is used.
The transducer converts the magnetic field into an electric quantity which is easily measured by the analogue and digital meters.
Question : 33
Which of the following loads can cause a serious frictional error in an induction type single-phase energy meter?
Frictional forces at the rotor bearings and in the counting (or register) mechanism cause a noticeable error, especially at light loads.
At light loads, the torque due to friction adds considerably to the braking torque on the disc rotor.
Since friction torque is not proportional to the speed but is roughly constant it can cause a considerable error in meter reading.
This error can be reduced by making the ratio of the shunt magnet flux φ2 and series magnet flux φ1 large with the help of two shading rings (or shading bands).
Question : 34
Find the equation for amplification factor (βdc) for the common emitter transistor. Consider dc collector current is IC, dc base current is IB and dc emitter current is IE
For a transistor, the base current, the emitter current, and the collector current are related as: IE = IB + IC
Where IC = βdcIB
βdc = Current gain of the transistor
Question : 35
What will be the efficiency of a Carnot’s engine, considering the temperature of the source as T1 and the temperature of the sink as T2?
Carnot engine- A theoretical thermodynamic cycle proposed by Leonard Carnot.
This engine gives the maximum possible efficiency that a heat engine can have during the conversion process of heat into work or vice-versa, working between two reservoirs.
Question : 36
What is the purpose of Switched Mode Power Supply (SMPS)?
The modern switch mode power supply, or SMPS, uses solid-state switches to convert an unregulated DC input voltage to a regulated and smooth DC output voltage at different voltage levels.
Question : 37
Which of the following devices converts the AC Supply of one frequency into an AC supply of a different frequency?
Cyclo-conveters are used to convert a fixed AC to a variable magnitude AC.
A device which converts input power at one frequency to output power at different frequency with one stage conversion is called cyclo-converter.
Question : 38
What is the term used for One complete to and fro motion in Simple harmonic motion?
One complete to and fro motion of the particle about its mean position is called oscillation.
Time taken by the body to complete one oscillation is called time period.
Question : 39
Which of the following statements is true for a series circuit in below resonant frequency?
Question : 40
A variable reluctance stepper motor has 8-number of windings in the stator and 6 number of teeth on the rotor. Find the step angle.
Step angle of the variable reluctance stepper motor is given by
Where Ns = Number of stator teeth
Nr = Number of rotor teeth
Given that, Nr = 6
Ns = 8
∴ The stepping angle can be calculated as
β = 15°
Question : 41
A stepping motor has 8-main poles which have been castellated to have 4 teeth each. If the rotor has 40 teeth, calculate the stepping angle.
Step angle of the hybrid stepper motor is given by
Ns = Number of stator teeth
Nr = Number of rotor teeth
Nr = 40
Ns = 8 x 4 = 32
∴ stepping angle can be calculated as
β=(40−32)/(40×32) × 360°
β = 2.25°
Question : 42
Which of the following statements is NOT true for HVDC transmission?
AC Needs More Insulation Than DC for the Same Working Voltage Level.
For the same working voltage, the potential stress on the insulation is less than in case of DC system than that AC system. Therefore , a DC line requires less insulation.
Question : 43
What is the economic voltage between lines in 3-phase system where V is the line voltage in kV, L is the distance of transmission line in km and P is the maximum power per phase to be delivered in a single circuit?
Economical transmission voltage for a 3 phase AC system is given as
Where, V = line voltage in kV
P = maximum power per phase (in kW) to be delivered over single circuit
L = distance of transmission in km
Question : 44
A moving coil instrument, whose resistance is 15 Ω, gives a full scale deflection with a voltage of 10 mV. This instrument is to be used with a series multiplier to extend the range to 1 V. Find the value of the multiplier resistance
Full-scale deflection voltage (Vm) = 10 mV
Meter resistance (Rm) = 15 Ω
Required full scale reading (V) = 1 V
Where m=V/Vm=1V/10 mV=100 V
Question : 45
Which of the following is NOT true for the squirrel cage induction motor when compared to the slip ring induction motor?
Squirrel Cage Induction Motor
3 phase squirrel cage induction motor is a type of 3-ϕ induction motor based on the principle of electromagnetism.
It is called a ‘squirrel cage’ motor because the rotor inside of it looks like a squirrel cage and is known as a squirrel cage rotor.
It is also known as short-circuited rotor type motor.
It doesn’t need a slip ring and brush assembly.
Airgap between the stator and rotor is uniform.
External resistance cannot be introduced in the rotor circuit.
|Slip ring induction motor||Squirrel cage induction motor|
|It has a slip ring type rotor||It has a squirrel cage type rotor|
|Cylindrical laminated core with parallel slots and each slot consist one bar||The slots of the rotor are not parallel but are skewed|
|Construction is complicated||Construction is simple|
|We can add external resistance to the rotor||The rotor bar is permanently shorted at the end of the ring; thus, it is not possible to add any external resistance|
|The rotor resistance starter can be used||Rotor resistance starter cannot be used|
|Starting torque is high||Starting torque is low|
|Brushes are present||Brushes are absent|
|The air gap between the stator and rotor is non-uniform.||The air gap between the stator and rotor is uniform.|
|Frequent maintenance is required||Less maintenance required|
|The power factor is low||Power factor is high|
|Speed control is possible||Speed control is not possible|
Question : 46
Which of the following statements is true for E-MOSFET?
A MOSFET can function in two ways
- Depletion Mode
- Enhancement Mode
When there is no voltage across the gate terminal, then the device does not conduct. When there is the maximum voltage across the gate terminal, then the device shows enhanced conductivity.
E-MOSFET operates only in the enhancement mode and has no depletion mode.
Question : 47
Earth leakage circuit breaker is arranged to operate very quickly when _____.
An Earth-leakage circuit breaker (ELCB) is a safety device used in electrical installations (both residential and commercial) with high Earth impedance to prevent electric shocks.
It detects small stray voltages on the metal enclosures of electrical equipment, and interrupts the circuit if a dangerous voltage is detected.
An earth leakage circuit breaker (ELCB) with a function of detecting a leakage current which backflows while cutting off an electric leakage is disclosed.
Earth leakage circuit breaker is arranged to operate very quickly when extremely low leakage current flows.
Question : 48
Arrange the type of Lamps in ascending order according to their average lumens/watt.
Luminous efficiency of given lamps
Incandescent lamps- 15 lumens per watt
Halogen lamps-25 lumens per watt
Fluorescent lamps-45 to 100 lumens per watt.
Low pressure sodium lamps-50 to 160 lumens per watt.
So ascending order of lumens/watt is Incandescent lamps, Halogen lamps, Fluorescent lamps, Low pressure sodium lamps.
Question : 49
Which of the following is true for the single-phase induction motor compared to the three-phase induction motor?
The single-phase motor is simple in construction, reliable, and economical compared to three-phase induction motors.
The three-phase motor is complex in construction and costly.
Question : 50
Which of the following disadvantages is true for the oil filled cables?
In case of oil filled cables, the channels or ducts are provided within or adjacent to the cores, through which oil under pressure is circulated.
1. The thickness of insulation required is less hence smaller in size and weight.
2. The thermal resistance is less hence current carrying capacity is more.
3. The possibility of voids is completely eliminated.
4. The allowable temperature range is more than solid type cables.
5. Reduced possibility of earth fault. This is because in case of any defect in lead sheath, oil leakage starts, which can be noticed before earth fault occurs.
6. Perfect impregnation is possible.
1. The initial cost is very high.
2. The long length are not possible.
3. The oil leakage is serious problem hence automatic signalling equipment is necessary.
4. The laying of cable is difficult and must be done very carefully.
5. Maintenance of the cables is also complicated.
Question : 51
Which of the following is true for the spring control as a controlling force for measuring instruments?
Spring Control Method-This is the most common method of providing controlling torque, in electrical instruments. A spiral hairspring made of some non-magnetic material like phosphor bronze is attached to the moving system of the instrument as shown in the figure.
Springs also serve the additional purpose of leading current to the moving system (i.e. operating coil).
With that deflection of the pointer, the spring is twisted in the opposite direction. This twist in the spring provides the controlling torque.
The amount of controlling torque produced will be proportional to the angle of deflection (θ) of the pointer, whereas the deflecting torque (Td) depends upon the current flowing through the coil i.e., Td increases with an increase in current and vice-versa. At steady state
Since current is directly proportional to the deflection angle, uniform scales can be graduated.
The springs used are usually made up of low resistance bronze alloy and consist of a large number of turns to avoid deformation in the spring.
Question : 52
Which logic instruction is used in the 8085 microprocessors to complement the contents of the accumulator?
In 8085 Instruction set, logical type there is one complement instruction with the mnemonic CMA.
It actually stands for “CoMplement the Accumulator”.
It performs1’s complement operation on the current contents of Accumulator, and the result is stored back in the Accumulator replacing its previous contents.
Question : 53
The peak anode current an SCR can handle for a short duration is known as _______.
The peak anode current in SCR can handle for a short duration is known as surge current rating.
Surge current rating specifies the maximum non-repetitive or surge current that the SCR can withstand for a limited number of times during its life span.The manufacturers specify the surge rating to accommodate the abnormal conditions of SCR due to short circuits and faults. If the peak amplitude and the number of cycles of the surge current are exceeded, the SCR may get damaged.
Question : 54
How is the breaking capacity of the circuit breaker calculated?
Breaking capacity of a circuit breaker in terms of MVA given as follows
MVA = √3 x KV x KA
MVA = Breaking capacity of a circuit breaker kV = Rated voltage kA = Rated breaking current
Or Breaking capacity = Rated symmetrical breaking current × Rated service voltage × √3
Symmetrical making current = 2.55 × symmetrical breaking current
Question : 55
A body is thrown with a velocity of projection 98 m/s at an angle of projection 45°. Find the maximum height it can attain.
Given Velocity of projection = vo = 98 m/s, Angle of projection = θ = 40o, g = 9.8 m/s2.
The maximum height reached is given by
H= 982 sin245/2×9.8
H= 982 (1/2)/2×9.8
Question : 56
Identify the DC link configuration for HVDC transmission given in the above figure.
Homopolar link– It has two conductors of the same polarity usually negative polarity, and always operates with earth or metallic return.
In the homopolar link, poles are operated in parallel, which reduces the insulation cost.
The homopolar system is not used presently.
Question : 57
Which of the following is a non-conventional source of energy?
Non-conventional sources of energy are the energy sources which are continuously replenished by natural processes. These cannot be exhausted easily, can be generated constantly so can be used again and again, e.g. solar energy, wind energy, tidal energy, biomass energy and geothermal energy etc.
|Conventional sources of energy||Non-conventional sources of energy|
|These sources of energy are not abundant, present in limited quantity, e.g. coal, petroleum, natural gas.||These sources of energy are abundant in nature, e.g. solar energy, wind energy, tidal energy, biogas from biomass etc.|
|They have been in use for a long time.||They are yet in development phase over the past few years.|
|They are not replenished continuously. They are formed over a million years.||They are replenished continuously by natural processes.|
|They are called non-renewable sources of energy.||They are called renewable sources of energy.|
|They can be exhausted completely due to over-consumption except for hydel power.||They cannot be exhausted completely.|
|They pollute the environment by emitting harmful gases and also contribute to global warming.||They are environment-friendly, do not pollute the environment.|
|They are commonly used for industrial and commercial purposes.||They are used commonly used for household purposes.|
|Heavy expenditure is involved in using and maintaining these sources of energy.||Using these sources is less expensive.|
|They are used extensively, at a higher rate than the non-conventional sources.||They are not used as extensively as conventional sources.|
Question : 58
Which of the following is NOT true for the Core type transformer?
In core type transformer coils used are Concentric Winding or Cylindrical Winding.
|Basis for Comparison||Core Type Transformer||Shell Type Transformer|
|Definition||The winding surround the core.||The core surround the winding.|
|Lamination Shape||The lamination is cut in the form of the L strips.||Lamination are cut in the form of the long strips of E and L.|
|Cross Section||Cross-section may be square, cruciform and three stepped||The cross section is rectangular in shape.|
|Coils||Concentric Winding or Cylindrical Winding.||Sandwich or Disc Winding|
|Flux||The flux is equally distributed on the side limbs of the core.||Central limb carry the whole flux and side limbs carries the half of the flux.|
|Winding||The primary and secondary winding are placed on the side limbs.||Primary and secondary windings are placed on the central limb|
|Natural Cooling||Does not Exist||Exist|
Question : 19
Which of the following grounding systems is also referred to as arc suppression coil grounding?
Resonant grounding is also known as Peterson coil neutral grounding or ground fault neutralizer or arc suppression coil.
In resonant neutral grounding, the arc resistance is reduced to such a small value that it is usually self-extinguishing.
Resonant grounding is also referred to as arc suppression coil grounding.
Question : 60
How much foot-candles of illumination is recommended for severe and prolonged visual tasks, such as fine engraving, and discrimination and inspection of fine details of low contrast?
Class of task
Recommended foot candles
Precision work to a high degree of accuracy, tasks requiring rapid discrimination and response
Severe and prolonged visual tasks, such as fine engraving, and discrimination
and inspection of fine details of low contrast.
Prolonged critical tasks, such as proof reading, type-setting, drawing, fine
machine work, fine assembling, sewing on dark goods.
Visual tasks, such as detailed office work, reading, skilled bench work,
sewing on light goods, and retail shops.
Less exacting visual tasks such as in general offices, on large assembly work
and in class rooms.
Work of simple character not involving attention to details
Casual observation where no specific task is performed