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# Multiple choice question for engineering

## Set 1

1. The amount of energy received in unit time on a unit area perpendicular to the sun’s direction at the mean distance of the earth from the sun is called ________
b) Solar constant
d) Air Mass

Answer: b [Reason:] The amount of energy received in unit time on a unit area perpendicular to the sun’s direction at the mean distance of the earth from the sun is called solar radiation. It is defined as the solar energy receiving at the top of the atmosphere, denoted by Isc.

2. What is ‘n’ in the following solar intensity formula?
I = Isc {1 + 0.033cos (360n/365)}
a) Day of the year
b) Month of the year
c) The year
d) Week of the year

Answer: a [Reason:] The following ‘n’ denotes day of the year in the formula. Since the distance between sun and earth varies, extra-terrestrial flux also varies. Earth is closest to the sun in the summer and farthest away in the winter.

3. When the sun is directly on the top of head, it as referred to _________
a) Zenith
b) Azimuth
c) Declination
d) Hour angle

Answer: a [Reason:] When the sun is directly on the top of the head, it is referred to as sun at zenith. The zenith is an imaginary point directly “above” a particular location, on the imaginary celestial sphere. The zenith is the “highest” point on the celestial sphere.

4. Path length of radiation through the atmosphere to the length of path when the sun is at zenith is called ___________
a) Declination
b) Air mass
c) Azimuth
d) Solar Constant

Answer: b [Reason:] Path length of radiation through the atmosphere to the length of path when the sun is at zenith is called Air mass. Air mass, m = Cos (altitude angle), except for very low solar altitude angles. m = 1; When the sun is at the zenith m = 2; When zenith angle is 60o m = 3; sec (θz) for m>3.

5. Radiation intensity ‘I’ normal to the surface is given by __________
a) ICosθ
b) Itanθ
c) ICotθ
d) Isinθ

Answer: a [Reason:] I = ICosθ, Let θ = Angle between an incident beam radiation I and the normal to the plane surface. And the θ is referred to as incident angle. And further by this formula latitude angle, declination, hour angle, zenith angle and solar azimuth angles are found out.

6. Angle made by radial line joining the location to the centre of the earth with the projection of the line on the equatorial plane is called _________
a) Latitude
b) Zenith angle
c) Hour angle
d) Declination

Answer: a [Reason:] Angle made by radial line joining the location to the centre of the earth with the projection of the line on the equatorial plane is called latitude. And it is denoted by φl. It is also given by the angular distance north or south of the equator measured from the centre of the earth.

7. Angular distance of sun’s rays north or south of the equator is called _______
a) Declination
b) Hour angle
c) Latitude
d) Air mass

Answer: a [Reason:] Declination is the angular distance of sun’s rays north or south of the equator. It is the angle between the line extending from the centre of the sun to the centre of the earth and the projection of this line upon earth’s equatorial plane.

8. By which of the following symbol is solar Declination denoted by ____________
a) δ
b) ρ
c) Δ
d) γ

Answer: a [Reason:] Solar declination is denoted by Greek letter δ (DELTA). Solar declination is the angle between the earth-sun line and the equatorial plane. Solar declination varies throughout the year. And is given by cooper equation, δ = 23.45sin [(360/365) (284+n)] ∵n is day of the year.

9. The angle through which the earth must turn to bring the meridian of a point directly in sun’s rays is called __________
a) Hour angle
b) Declination
c) Latitude
d) Air mass

Answer: a [Reason:] The angle through which the earth must turn to bring the meridian of a point directly in sun’s rays is called Hour angle. And it is denoted by Greek letter ω (OMEGA). It is measured from noon based on the solar local time (LST).

10. Solar Altitude is also called as ________
a) Declination
b) Altitude angle
c) Zenith angle
d) Azimuth angle

Answer: b [Reason:] The vertical angle between the projection of the sun’s rays on the horizontal plane and the direction of sun’s rays passing through the point s called solar altitude and is also referred to altitude angle and is denoted by Greek letter α (ALPHA).

11. The angle between the sun’s rays and a line perpendicular to the horizontal plane through angle the beam of the sun and vertical is called __________
a) Solar Azimuth angle
b) Zenith angle
c) Altitude angle
d) Declination

Answer: b [Reason:] The angle between the sun’s rays and a line perpendicular to the horizontal plane through angle measured from the north to the horizontal projection of rays is called zenith angle. And it is denoted by θz.

12. The solar angle in degrees along the horizon east or west of north or it is the horizontal angle measured from north to the horizontal projection of sun’s rays is called ___________
a) Solar azimuth angle
b) Zenith angle
c) Altitude angle
d) Declination

Answer: a [Reason:] The solar angle in degrees along the horizon east or west of north or it is the horizontal angle measured from north to the horizontal projection of sun’s rays is called solar azimuth angle. And it is denoted by Greek letter γs (GAMMA).

## Set 2

1. Which of the following energy has the greatest potential among all the sources of renewable energy?
a) Solar energy
b) Wind Energy
c) Thermal energy
d) Hydro-electrical energy

Answer: a [Reason:] Solar energy has the greatest potential of all the sources of renewable energy which comes to the earth from sun. This energy keeps the temperature of the earth above that in colder space, causes wind currents in the ocean and the atmosphere, causes water cycle and generates photosynthesis in plants.

2. What is the rate of solar energy reaching the earth surface?
a) 1016W
b) 865W
c) 2854W
d) 1912W

Answer: a [Reason:] The solar energy reaching the surface of the earth is about 1016W whereas the worldwide power demand is 1013W. That means solar energy gives us 1000 times more energy than our requirement.

3. What is total amount of solar energy received by earth and atmosphere?
a) 3.8 X 1024 J/year
b) 9.2 X 1024 J/year
c) 5.4 X 1024 J/year
d) 2.1 X 1024 J/year

Answer: a [Reason:] Even if we use 5% of this energy, it is more than 50 times our requirement. The total solar radiation absorbed by the earth and its atmosphere is 3.8 X 1024 Joules/year. Except that it is distributed over the area of earth.

4. Which is most common source of energy from which electricity is produced?
a) Hydroelectricity
b) Wind energy
c) Coal
d) Solar energy

Answer: c [Reason:] Coal is the most common source of energy that is being used since industrialization. Modern steam boilers can burn coal in any of its form as a primary fuel. Different ranks of coal available are peat, lignite, bituminous and anthracite.

5. Oil is estimated to last for ________ more.
a) 100 years
b) 500 years
d) 800 years

Answer: a [Reason:] Almost 40% of energy needs is met by oil alone. With present consumption and a resource of 250,000 million tonnes of oil, it is estimated to be last for only 100 years, unless more oil is discovered. Major chunk of oil comes from petroleum.

6. Complete the following reaction.
H2O + CO2 → _______

a) CH2O + O2
b) CO2 + O2
c) H + CO2 + O2
d) CH2O + H2O + O2

Answer: a [Reason:] H2O + CO2 → CH2O + O2 ∵under solar energy CH2O is stable at low temperature but breaks at higher temperature releasing heat equal to 469 Kj/mole.

7. In what form is solar energy is radiated from the sun?
c) Electromagnetic waves
d) Transverse waves

Answer: c [Reason:] Solar energy is radiated from the sun in the form of electromagnetic waves of shorter wavelength of 0.2 to 0.4 micrometers. Out of all the solar energy radiations reaching the earth’s atmosphere, 8% is ultraviolet radiation, 40% is visible range light and 46% is by infrared radiation.

8. What does MHD stands for in the energy field?
a) Magneto Hydro Dynamic
b) Metal Hydrogen Detox
c) Micro Hybrid Drive

Answer: a [Reason:] Magneto hydro dynamic is a generator which is used for direct conversion of thermal energy into electrical energy. They work on faraday principle. When an electric conductor moves across a magnetic field, electric current is produced.

9. Solar radiation which reaches the surface without scattering or absorbed is called _____________

Answer: a [Reason:] Solar radiation that has not been absorbed or scattered and reaches the ground from the sun is called direct radiation or beam radiation. It is the radiation which produces a shadow when interrupted by an opaque object.

10. The scattered solar radiation is called ____________

Answer: c [Reason:] Diffuse radiation received from the sun after its direction has been changed by reflection and scattering by the atmosphere. Since the solar radiation is scattered in all direction in the atmosphere, diffuse radiation comes to the earth from all parts of the sky.

11. Solar radiation received at any point of earth is called ______________
a) Insolation
d) Infrared rays

Answer: a [Reason:] Insolation is the total solar radiation received at any point on any point on the earth’s surface. In other words insolation is the sum of the direct and diffuse radiation. More specifically insolation is defined as the total solar radiation energy received on a horizontal surface of unit area on the ground in unit time.

12. Insolation is less ____________
a) when the sun is low
b) when the sun right above head
c) at night
d) at sun rise

Answer: a [Reason:] The insolation at a given point or location on the earth’s surface depends among other factors, on the altitude of the sun in the sky. As a result of absorption and scattering, the insolation is less when the sun is low in the sky than when it is higher.

13. HHW stands for ____________
a) High and Low water
b) High Level Waste
c) Heated Low Level water
d) High and Low Waste

Answer: b [Reason:] These are generated in reprocessing of spent fuel. They contain all fission products and contain of the transuranium elements not separated during reprocessing. Such wastes are to be disposed of carefully.

14. What is unit of nuclear radiation?
a) Reaumur
b) Roentgen
c) Rankine
d) Pascal

Answer: b [Reason:] Units of nuclear radiation is Roentgen- amount of radiation which will on passing through pure air under standard condition produce 1 electrostatic unit of ions/cm3 of air -> 86.9 ergs of energy absorbed/gm of air.

15. Which type of fuel is removed from the reactor core after reaching end of core life service?
a) Burnt Fuel
b) Spent fuel
c) Engine oil

Answer: b [Reason:] Spent fuel is the unprocessed fuel that is removed from the reactor core after reaching end of core life service. It is removed and then stored for 3 to 4 months under water in the plant site to give time for the most intense radioactive isotopes to decay.

## Set 3

1. Angle made by plane surface with horizontal is called ________
a) Slope
b) Altitude angle
c) Zenith angle
d) Hour Angle

Answer: a [Reason:] The slope is the angle made by the plane surfaces with the horizontal. It is considered positive for surfaces slopping towards the south and negative for surface slopping towards the north. Different types of measurements are calculated by slopes.

2. The angle of deviation of the normal to the surface from the local meridian is called as _________
a) Surface azimuth angle
b) Solar azimuth angle
c) Solar altitude
d) Hour angle

Answer: a [Reason:] Surface azimuth angle is the angle of deviation of the normal to the surface from the local meridian, the zero point being south, east positive and west negative. And surface azimuth is different where it is an angle on a horizontal plane between the normal to a vertical surface and the north-south direction line.

3. The angle being measured from a plane and which is equal to angle between the beam of rays and normal to the plane is called __________
a) Incident angle
b) Azimuth angle
c) Hour angle
d) Declination

Answer: a [Reason:] The angle being measured from a plane and which is equal to angle between the beam of rays and normal to the plane is called as incident angle. And it is denoted by Greek letter θ (Theta). The angle of incidence (θ) is the angle between the sun’s rays irradiated on a surface and the line normal to this surface.

4. The vector sum of the components along the line normal of the titled surface in a direction normal to the tilted surface is called as__________
a) Solar intensity
b) Declination
c) Incident angle
d) Hour angle

Answer: a [Reason:] The solar intensity at a direction normal to the tilted surface is the vector sum of the components along the line normal of the tilted surface. And is given by formula, IΣ = IDN cosθΣ Where IDN = solar intensity irradiated on a surface normal to the sun’s rays.

5. The time from sunrise to sunset is termed as _______________
a) Slope
b) Day length
c) Local solar time
d) Solar intensity

Answer: b [Reason:] The time from sunrise to sunset is termed as day length. On earth, daytime is roughly the period of the day during which any given point in the world experiences natural illumination from especially direct sunlight. Daytime occurs when the sun appears above the local horizon, that is, anywhere on the globe’s hemisphere facing the Sun. During daytime, an observer sees indirect sunlight while in the shade, which includes cloud cover.

6. LST stands for __________
a) Local standard time
b) Local solar temperature
c) Low surface temperature
d) Land surface temperature

Answer: b [Reason:] Local solar time is also known as local apparent time which is the time used for calculating the hour angle. The local solar time is obtained from the standard time observed on a clock by making two corrections. First, is taking different longitudes between the locations and second is correction due to small perturbations of earth’s orbit and rate of rotation.

7. How much would be the angle of declination on DECEMBER 21 at 0900 h (LAT). The collector s located in New Delhi (28o35’N, 77o12’E) and is tilted at an angle of 36o with the horizontal and is pointing south?
a) -44.28 o
b) -28.92 o
c) -23.45 o
d) -42.22 o

Answer: c [Reason:] In the case γ= 0o, on December 21, n=355

8. What is angle of declination on 305th day of year and what day is it?
a) -23.26o, November 2
b) -15.06o, November 1
c) -18.96o, November 2
d) -10.52o, November 1

9. What is the angle of declination on May 12 considering it’s a leap year?
a) 20.34 o
b) 22.85 o
c) 29.42 o
d) 12.4 o

Answer: a [Reason:] Angle of declination on May 21 in leap year is 142nd day of the year.

10. What is the angle of declination on 60th day of the leap year?
a) -8.29
b) 8.29
c) 4.82
d) 12.44

11. Which type of device is used to measure solar irradiance on a planar surface?
a) Pyranometer
c) Gardon gauge
d) Pyrheliometer

Answer: a [Reason:] A Pyranometer is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density from the hemisphere above within a wavelength range 0.3μm to 3μm.

12. Instrument used to measure direct beam of solar irradiance is called ____________
a) Pyranometer
c) Gardon gauge
d) Pyrheliometer

Answer: d [Reason:] A Pyrheliometer is the device used to measure direct beam solar irradiance. Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded.

## Set 4

1. The method of removing soot from the power plant machineries is known as _________
a) Soot cleansing
b) Centrifugation
c) Soot blowing
d) Bioleaching

Answer: d [Reason:] The products of combustion cling to the water tubes, economizer tubes, air preheater tubes and super heater tubes. This lowers the efficiency of the plant by reducing heat transfer. So, regular removal of soot or dust is necessary this method is known as soot blowing.

2. Why nozzle tubes are provided in the soot blowers?
a) To moistures the dust
b) To admit high pressure steam
c) To blow away the soot
d) To suck in the dust and exhaust it at high pressure

Answer: b [Reason:] The usual form for the smaller boilers is a dead-end tube projecting through the setting and extending into the tube banks. A number of small lateral nozzles are provided and the external head is arranged so that high pressure steam can be admitted to the tube and at the same time the tube is rotated around its axis.

3. Which type of blower advances into the furnace, cleans and comes back?
a) Wall blower
b) Retractable blower
c) Air heat blower
d) Insert able kinetic blower

Answer: b [Reason:] Soot blower consists of a set of tubes fitted with nozzles carrying high velocity jet of steam or air. In the hotter parts of the boiler, the blower advances into the furnace, cleans the heat transfer surfaces and comes back. This type of soot blower is known as retractable soot blower.

4. Why are there number soot blower units in large blower?
a) To obtain high efficiency
b) To clean the boiler in short amount of time
d) For easy replacement

Answer: c [Reason:] Steam jets clean soot from heating surface in their proximity, but the action is limited in extent in a close array such as tube banks; hence several units may be needed to clean the boiler adequately. It is quite common to see 8 to 16 units in a large boiler.

5. Why operating heads of soot blowers are automated?
a) Because they are tedious to operate manually
b) Because they cannot be handled at once
c) Because they are positioned at different parts of machine
d) Because it is quicker by automation

Answer: a [Reason:] Soot blowers are tedious to operate manually, and since must not all be operated simultaneously, the operating heads are electric motor powered and operated by remote control on an automatic sequential basis.

6. Why on some boilers the draft system controls have to be positioned abnormally in soot blowers?
a) To avoid the soot being blown back into boiler
b) To get a good grip for blowing out the soot from the boiler
c) due to lack of space in the boiler
d) To avoid the heat of boiler affecting the soot blowers

Answer: a [Reason:] On some boilers the automatic draft system controls have to be positioned for abnormally high draft before beginning the soot blowing operation; otherwise the release of stem into the setting may blow soot and smoke into the boiler room.

7. In which state would be the soot blower when it’s not in use?
a) Dry and cooled
b) Dry and uncooled
c) Wet and cooled
d) Dry and hot

Answer: b [Reason:] When not in use the soot blower tube of the system would be dry and uncooled, and subject to gas temperatures. Even with alloy tubes the deterioration is relatively rapid on units normally experiencing high gas temperatures.

8. What is the advantage of using retractable soot blower?
a) Has high blowing capacity compared to steam and wall blowers
b) Protects from high temperatures when not in use
c) Consumes less amount of electricity
d) Produces less amount of noise

Answer: b [Reason:] Retractable blower, though more expensive initially, have the advantage of protection from high temperature when not in use. Also, using only two travelling nozzles, the jet can be larger without excessive steam drain, and the projected blast distance is greater.

9. Why is it necessary to observe temperature drops in the soot blower?
a) To avoid net loss
b) To avoid the soot getting struck in soot blower
c) To avoid over usage
d) To avoid overconsumption of electricity

Answer: a [Reason:] It is necessary to observe temperature drops routinely. Obviously if the temperature drops 24oC after blowing, the interval might well be decreased, where as if 12oC were observed; it could represent a net loss because the value of the steam used was more than that of the increment of flue gas heat.

10. Is there a chance of fire due to the accumulation soot inside the boiler?
a) True
b) False

Answer: a [Reason:] A soot fire can be damaging to a boiler because it can cause localized hotspots to occur in the tubes. These hotspots may reach temperatures that weaken the materials of the tubes. Soot blowers reduce the risk of soot fires and their resulting damage.

## Set 5

1. In which mode of transport are rotary car dumpers used?
b) Rail transport
c) Transport by sea or river
d) Inside the plant handling

Answer: b [Reason:] Depending on the mode of transport viz. by sea or road or rail, coal unloading done. Rotary car dumpers are used when the transport is done by rail also coal towers and coal accelerators are used. Coal towers, unloading bridges and self unloading boats are used if the outplant handling of the coal is by sea or river.

2. What is the function of sizer in coal handling?
a) To separate the coal depending on size
b) To check the amount of fuel that is supplied
c) To pick the coal of required size
d) To divert the coal flow into different burners

Answer: c [Reason:] The function of the sizer is to pick the coal of requires size, which is coming from the crusher. The un-sized coal is fed back to the crusher. The function of crusher is to crush the coal to uniform size.

3. What is the function of magnetic separator in coal handling?
a) To remove impurities
b) To separate bituminous coal
c) To remove iron particles
d) To separate metal contents

Answer: c [Reason:] The function of the magnetic separator is to remove iron particles which otherwise may choke the burners besides damaging other equipments. The iron particles are trapped by the magnetic pulley while the belt carrying coal passes over it. It is collected in a chute.

4. What is the purpose of bucket elevators in coal handling?
a) Used to move coal horizontally
b) Used to lift coal vertically
c) Used to separate the crushed coal and pulverized coal
d) Used to pour the coal vertically at right angles into furnace

Answer: b [Reason:] Centrifugal and continuous types of bucket elevators are used for lifting coal to moderate height (about 30m). It consists of buckets fixed to a chain moving over two sprockets. The buckets carry coal from bottom and discharge at the top at a speed ranging between 15 m/min to 36m/min.

5. What is the function of Gab bucket conveyor in coal handling?
a) To lift the coal vertically
b) To crush the coal
c) To move coal from one place to another
d) To separate crushed coal and powdered coal

Answer: c [Reason:] Grab bucket conveyor can grab as well as convey coal from one place to another. It is used with a crane or tower and it has different capacities. It is very essential when all other means of transporting coal is not viable. It has high initial cost but low operating cost.

6. Out of all conveyors which type of conveyor has a greater capacity to convey large amount of coal?
a) Belt conveyor
b) Chain conveyor
c) Screw conveyor
d) Scraper conveyor

Answer: a [Reason:] Belt conveyor is used for transporting large quantities of coal over long distances. It consists of an endless belt made of rubber, balata or canvass running over pulleys or end drums. It is economical means of coal transportation at rapid rate.

7. What is the distance at which belt conveyors can convey?
a) 100m
b) 200m
c) 50m
d) 500m

Answer: d [Reason:] Belt conveyors can handle upto 50 to 100t/h of load can be carried over a distance of about 500m. These conveyors can be used with inclination upto 20o to the horizontal moving at an average speed of 60 to 90 m/min. However it cannot be used for carrying coal at greater heights.

8. To what is helicoids screw in screw conveyor is attached?
a) To the shaft
b) To the inner case
c) To the bearings
d) To the outer casing

Answer: a [Reason:] Screw conveyor is used to transmit coal. It consists of an endless helicoids screw of diameter 150 mm to 500 mm wound around a rotating shaft. One end of the shaft is connected to the drive whereas the other end is supported by a bearing.

9. In what speed range does screw conveyor run at?
a) 60 – 80 rpm
b) 20 – 100 rpm
c) 60 – 120 rpm
d) 90 to 180 rpm