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Multiple choice question for engineering

Set 1

1. Greenhouse effect is not caused by?
a) CFC’s
b) Sulphur dioxide
c) Carbon dioxide
d) None of the mentioned

View Answer

Answer: a [Reason:] CFC’s aren’t responsible for the greenhouse effect.

2. In a four stroke cycle petrol engine, the inlet valve
a) opens at top dead centre and closes at bottom dead centre
b) opens at 20° before top dead centre and closes at 40° after bottom dead centre
c) opens at 20° after top dead centre and closes at 20° before bottom dead centre id may open or close anywhere
d) none of the mentioned

View Answer

Answer: b [Reason:] In a four stroke cycle petrol engine, the inlet valve opens at 20° before top dead centre and closes at 40° after bottom dead centre.

3. Which of the following does not relate to a compression ignition engine?
a) Fuel injector
b) Fuel pump
c) Governor
d) Carburettor

View Answer

Answer: d [Reason:] Carburettor isn’t used in a compression ignition engine, instead it is used in spark ignition engine.

4. The theoretically correct mixture of air and petrol is
a) 20:1
b) 15:1
c) 40:1
d) 50:1

View Answer

Answer: a [Reason:] The theoretically correct mixture of air & petrol is 20:1.

5. The injection pressure in a diesel engine is about
a) 10 bar
b) 100 bar
c) 150 bar
d) 300 bar

View Answer

Answer: b [Reason:] The injection pressure in a diesel engine is about 100 bar.

6. The pressure at the end of compression, in diesel engines, is approximately
a) 10 bar
b) 15 bar
c) 20 bar
d) 35 bar

View Answer

Answer: d [Reason:] The pressure at the end of compression, in diesel engines, is approximately 35 bar.

7. The function of a distributor in a coil ignition system of I.C. engines is
a) to distribute spark
b) to distribute power
c) to time the spark
d) to distribute current

View Answer

Answer: c [Reason:] Distributor in a coil ignition system of an IC Engine times the spark produced.

8. Brayton cycle corresponds to?
a) IC Engines
b) Gas Turbines
c) Both of the above mentioned
d) None of the above mentioned

View Answer

Answer: b [Reason:] Gas Turbines are based on Brayton cycle.

9. Intercooling is done in?
a) CI Engines
b) SI Engines
c) Gas Turbines
d) None of the mentioned

View Answer

Answer: c [Reason:] Intercooling is done in Gas Turbines.

10. A Gas Turbine is also known as?
a) Compression Turbine
b) Compensation Turbine
c) Combustion Turbine
d) None of the mentioned

View Answer

Answer: c [Reason:] Combustion Turbine is yet another name of Gas Turbines.

Set 2

1. The function of moderators in nuclear reactor is to
a) absorb the secondary neutrons
b) slow down the secondary neutrons
c) control the chain reaction
d) none of the mentioned

View Answer

Answer: b [Reason:] The function of moderators in nuclear reactor is to slow down the secondary neutrons.

2. Which of the following is not used as a nuclear fuel cladding material
a) Cadmium
b) Zircalloy
c) Ceramics
d) Stainless Steel

View Answer

Answer: a [Reason:] Cadmium is not used as a nuclear fuel cladding material.

3. Nuclear fuel complex, Hyderabad is engaged in the job of
a) processing of uranium ore
b) manufacture of nuclear fuel elements/assemblies
c) treatment of spent fuel
d) none of the mentioned

View Answer

Answer: b [Reason:] The Hyderabad complex is involved in the manufacturing of nuclear fuel elements.

4. Which one is different for the neutral atoms of the isotopes of an element ?
a) Number of electrons
b) Atomic weight
c) Atomic number
d) Number of Protons

View Answer

Answer: b [Reason:] The isotopes are atoms of the same element but with a different atomic weight.

5. Thorium can be converted into U-233 in a __________ reactor.
a) fast breeder
b) liquid metal reactor
c) Curtis reactor
d) none of the mentioned

View Answer

Answer: a [Reason:] Fast breed reactors are used to convert Thorium into U-233.

6. A moderator ______ the neutrons
a) accelerates
b) slows down
c) blocks
d) stops

View Answer

Answer: b [Reason:] The function of a moderator is to slow down fast moving neutrons thus controlling the extent of fission reaction.

7. __________ nuclear reactor does not require a heat exchanger to supply steam to power turbine.
a) pressurised water
b) boiling water
c) helium cooled
d) molten sodium cooled

View Answer

Answer: b [Reason:] Boiling water nuclear reactor does not require a heat exchanger to supply steam to power turbine.

8. If 4 gm of a radioisotope has a half-life period of 10 days, the half-life of 2 gm of the same istotope will be __________ days.
a) 10
b) 5
c) 20
d) 30

View Answer

Answer: a [Reason:] Applying Radioactive Decay law.

9. Thermal neutrons which are used to cause the fission of U-235 have energy __________ eV.
a) >1
b) <0.025
c) >200
d) 1-25

View Answer

Answer: b [Reason:] Thermal neutrons which are used to cause the fission of U-235 have energy < 0.025 eV.

10. Pick out the wrong statement.
a) Positron is heavier than a proton
b) A, β-ray particle is identical with an electron
c) The nucleus of a hydrogen atom is identical with a proton
d) Mass of an electron is about 1/1800th of the lightest nucleus

View Answer

Answer: a [Reason:] Positron is lighter than a proton.

11. Specific gravity of uranium and plutonium is about
a) 13
b) 9
c) 19
d) 27

View Answer

Answer: c [Reason:] Specific gravity of Uranium & Plutonium is about 19.

12. Which of the following types of nuclear reactors is most prone to radioactive hazards?
a) Gas cooled reactor
b) Molten Sodium Reactor
c) Boiling water reactor
d) Pressurised water reactor

View Answer

Answer: c [Reason:] Boiling water reactor is the most prone to radioactive hazards.

13. The velocity of thermal (slow) neutrons triggering nuclear fission reaction (having energy equal to 0.025 eV) is about __________ metres/second.
a) 1100
b) 2200
c) 3300
d) 4400

View Answer

Answer: b [Reason:] The velocity of thermal (slow) neutrons triggering nuclear fission reaction (having energy equal to 0.025 eV) is about 2200 m/sec.

14. Radioactive decay is a ________ change.
a) Physical
b) Chemical
c) Nuclear
d) None of the mentioned

View Answer

Answer: c [Reason:] Radioactive decay is a nuclear phenomenon.

Set 3

1. What is the value of “beta” if h represents the local enthalpy on the given expansion line at a given pressure & hf is the enthalpy of saturated water at that pressure?
a) h + hf
b) h x hf
c) h – hf
d) none of the mentioned

View Answer

Answer: c [Reason:] The expression for the value of “beta” if h represents the local enthalpy on the given expansion line at a given pressure & hf is the enthalpy of saturated water at that pressure is given as, Beta = h – hf.

2. The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser resprctively, is given by which of the following expression?
a) t = 0.5 (a x b)
b) t = 0.5 (a / b)
c) t = 0.5 (a + b)
d) t = 0.5 (a – b)

View Answer

Answer: d [Reason:] The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser respectively, is given by, t = 0.5 (a – b).

3. What happens to the feedwater that enters the economiser?
a) Feedwater is heated to the saturation temperature at the boiler pressure
b) Feedwater is heated to the boiler temperature at the saturation pressure
c) Feedwater is cooled to the saturation temperature
d) Feedwater is cooled at the boiler pressure

View Answer

Answer: a [Reason:] The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. Naturally, this is what happens to the feedwater in the Economiser.

4. The economiser can also be assumed as?
a) Feedwater cooler
b) Feedwater heater
c) Economiser has nothing to do with Feedwater
d) None of the mentioned

View Answer

Answer: b [Reason:] The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. Hence, it is assumed as ‘feedwater heater’.

5. The feedwater in the Economiser _________
a) is heated by bled turbine steam
b) is cooled by bled turbine steam
c) is heated by outgoing flue gases
d) is cooled by outgoing flue gases

View Answer

Answer: c [Reason:] The function of an economiser is to heat the feedwater to the saturation temperature at the boiler temperature. This heating of feedwater occurs by the heat given to the feedwater by outgoing flue gases.

6. The temperature rise from condenser to boiler saturation is divided __________ among the feedwater heaters for maximum gain in efficiency.
a) unequally
b) partially
c) equally
d) remains undivided

View Answer

Answer: c [Reason:] The total enthalpy rise or the temperature rise from condenser to boiler saturation is divided equally among the feedwater heaters for maximum gain in the efficiency.

7. What is the expression for enthalpy of each heater h heater if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters?
a) h heater = ( a-b )/ (n +1)
b) h heater = ( a-b ) x (n -1)
c) h heater = ( a-b ) + (n -1)
d) h heater = ( a-b ) – (n +1)

View Answer

Answer: a [Reason:] the expression for enthalpy of each heater h if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters is given by, h heater = ( a- b)/ (n +1).

8. If n denotes the number of heater, t denotes the overall temperature difference & T denotes the total temperature rise of feedwater. The expression for T is?
a) ( n/(n+1)) x t
b) ( n/(n-1)) x t
c) ( n/(n+1)) / t
d) ( n/(n+1)) – t

View Answer

Answer: a [Reason:] If n denotes the number of heater, t denotes the overall temperature difference & T denotes the total temperature rise of feedwater. The expression for T is given by the following relation, T = ( n/(n+1)) x t.

9. The expression for the overall temperature difference T is given by?
a) t = boiler saturation temperature – condenser temperature
b) t = boiler saturation temperature + condenser temperature
c) t = boiler saturation temperature x condenser temperature
d) t = boiler saturation temperature / condenser temperature

View Answer

Answer: a [Reason:] The expression for the overall temperature difference t is given by, t = boiler saturation temperature – condenser temperature.

10. Efficiency gain follows the law of?
a) diminishing forward motion
b) increasing return
c) decreasing return
d) none of the mentioned

View Answer

Answer: c [Reason:] The gain in cycle efficiency is proportional to the gain in feedwater temperature, the efficiency gain thereby follows the law of diminishing return with the increase in the number of heaters.

11. The number of heaters for a plant is fixed by?
a) Mass Balance
b) Energy balance
c) Heat balance
d) None of the mentioned.

View Answer

Answer: b [Reason:] The number of heaters for a plant is fixed by Energy Balance of the whole plant when it is found that cost of adding another heater does not justify the saving in heat supply or marginal increase in cycle efficiency.

12. The effect on the degree of regeneration due to an increase in feedwater temperature is?
a) degree of regeneration increases
b) degree of regeneration decreases
c) degree of regeneration remain same
d) degree of regeneration is optimised

View Answer

Answer: d [Reason:] An increase in feedwater temperature reduces the heat absorption from the outgoing flue gases in the economiser & may cause a reduction in boiler efficiency. The number of heaters & the degree of regeneration thus get optimised.

13. The expression for efficiency when a & b are two constants corresponding to alpha & beta and c corresponds to gamma, is?
a) Efficiency = 1 – ((b2))/((b + c)(a + b – c)))
b) Efficiency = 1 + ((b2))/((b + c)(a + b – c)))
c) Efficiency = ((b2))/((b + c)(a + b – c)))
d) Efficiency = 1 / ((b2))/((b + c)(a + b – c)))

View Answer

Answer: a [Reason:] The expression for efficiency when a & b are two constants corresponding to alpha & beta and c corresponds to gamma, is given as, Efficiency = 1 – ((b2))/((b + c)(a + b – c))).

14. What is the relation between a & c if a & c correspond to alpha & gamma respectively, for maximum efficiency of a cycle?
a) a = 3c
b) c = 2a
c) c = (a/3)
d) a = 2c

View Answer

Answer: d [Reason:] The relation between a & c if a & c correspond to alpha & gamma respectively, for maximum efficiency of a cycle is given by, c = (a/2).

15. The expression for efficiency gain due to regeneration if a, b, n correspond to alpha, beta, cycle efficiency respectively, is?
a) n = ((a x a x b)/((a + b)((a + 2b)2))
b) n = ((a x a x b)/((a – b)(a + 2b)2))
c) n = ((a x a x b)/((a + b)(a + b)2))
d) n = ((a x a x b)/((a + b)(a + 2b)3))

View Answer

Answer: a [Reason:] The expression for efficiency gain due to regeneration if a, b, n correspond to alpha, beta, cycle efficiency respectively is given by, n = ((a x a x b)/((a + b)(a + 2b)2)).

Set 4

1. For centrifugal pump impeller, the maximum value of the vane exit angle is
a) 100 to 150
b) 150 to 200
c) 200 to 250
d) 250 to 300

View Answer

Answer: c [Reason:] The maximum value of the vane exit angle is 200 to 250.

2. In which turbine the pressure energy of water is first converted into kinetic energy by means of nozzle kept close to the runner?
a) Impulse turbine
b) Reaction turbine
c) Both a and b
d) None of the mentioned

View Answer

Answer: a [Reason:] Impulse Turbine is the one in which pressure energy of water is first converted into kinetic energy by means of nozzle kept close to the runner.

3. The pressure of water is atmospheric and remains constant while passing over the runner in __________
a) Impulse turbine
b) Reaction turbine
c) Both a and b
d) None of the mentioned

View Answer

Answer: a [Reason:] The pressure of water is atmospheric and remains constant while passing over the runner in Impulse Turbine.

4. The energy of water entering the reaction turbine is _______
a) fully the kinetic energy
b) fully the pressure energy
c) partly the pressure energy and partly the kinetic energy
d) unpredictable

View Answer

Answer: c [Reason:] The energy of water entering the reaction turbine is partly the pressure energy and partly the kinetic energy.

5. Which of the following is an example of impulse turbine?
a) Propeller turbine
b) Francis turbine
c) Kaplan turbine
d) Pelton wheel

View Answer

Answer: d [Reason:] Pelton Wheel Turbine is an example of impulse Turbine.

6. The runner of __________ turbine always be under pressure of above atmospheric pressure
a) Turgo
b) Girand
c) Kaplan
d) None of the mentioned

View Answer

Answer: c [Reason:] The runner of Kaplan turbine always be under pressure of above atmospheric pressure.

7. What is the head of water available at turbine inlet in hydro-electric power plant called?
a) head race
b) tail race
c) gross head
d) net head

View Answer

Answer: d [Reason:] the head of water available at turbine inlet in hydro-electric power plant called Net Head.

8. Gross head is the difference between __________
a) head race and tail race
b) head race and net head
c) head race and friction losses
d) net head and friction losses

View Answer

Answer: a [Reason:] Gross head is the difference between head race and tail race.

9. Which of the following hydraulic turbines has a construction given in diagram below?
power-plant-questions-answers-pelton-wheel-turbine-q9
a) Kaplan turbine
b) Francis turbine
c) Pelton turbine
d) Propeller turbine

View Answer

Answer: c [Reason:] From the diagram above, it is clear that the turbine shown is a Pelton Wheel Turbine.

10. What is runaway speed of the runner of Pelton wheel?
a) maximum unsafe speed of the runner due to sudden increase in load on turbine
b) minimum safe speed of the runner due to sudden increase in load on turbine
c) maximum unsafe speed of the runner due to sudden decrease in load on turbine
d) minimum safe speed of the runner due to sudden decrease in load on turbine

View Answer

Answer: c [Reason:] The maximum unsafe speed of the runner due to sudden decrease in load on turbine is called runaway speed of the runner of Pelton wheel.

11. What is the formula for the velocity of water jet at the inlet of turbine?
Where,
H = Net head acting on Pelton wheel
Cv = coefficient of velocity of jet
a) V = Cv((gH)(1/2))
b) V = 2Cv((gH)(1/2))
c) V = Cv((2gH)(1/2))
d) V = 2Cv((gH)(1/2))

View Answer

Answer: c [Reason:] The relation between the various quantities mentioned above is given by, V = Cv((2gH)(1/2)).

12. Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.
a) cube of diameter
b) fourth power of diameter
c) diameter
d) square of diameter

View Answer

Answer: b [Reason:] Power required to drive a centrifugal pump is directly proportional to fourth power of its impeller.

13. In a reaction turbine, the draft tube is used
a) to increase the head of water by an amount equal to the height of the runner outlet above the tail race
b) to transport water to downstream
c) to run the turbine full
d) to prevent air to enter the turbine

View Answer

Answer: a [Reason:] In a reaction turbine, the draft tube is used to increase the head of water by an amount equal to the height of the runner outlet above the tail race.

14. The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is
a) high speed with radial flow at outlet
b) slow speed with radial flow at outlet
c) medium speed with radial flow at outlet
d) high speed with axial flow at outlet

View Answer

Answer: d [Reason:] The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is high speed with axial flow at outlet.

15. Which of the following pump is preferred for flood control and irrigation applications?
a) Reciprocating pump
b) Axial flow pump
c) Mixed flow pump
d) Centrifugal pump

View Answer

Answer: b [Reason:] Axial flow pump is preferred for flood control and irrigation applications.

Set 5

1. Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the
a) requirement of large volume of combustion chamber
b) incomplete combustion of coal
c) risk of explosion
d) chances of clinker formation

View Answer

Answer: c [Reason:] Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the risk of explosion owing to the reacting mixture.

2. The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C.
a) 100-150
b) 350-450
c) 700-850
d) 550-650

View Answer

Answer: b [Reason:] The temperature at which plastic layer formation takes place during carbonisation of coal varies from 350 to 450 °C.

3. Which of the following is not a by-product recovered in a high temperature coal carbonisation plant?
a) Benzol
b) Ethylene
c) Pitch-cresosote mixture (PCM)
d) Naphthalene

View Answer

Answer: b [Reason:] Apart from Ethylene all the others are by-products obtained in high temperature coal carbonisation plant.

4. Pick out the wrong statement.
a) Regulation of furnace temperature and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing
b) Low grade coal can be used, but generally high volatile matter coals are more suitable for making pulverised fuel
c) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal
d) None of the mentioned

View Answer

Answer: d [Reason:] All the mentioned statements are correct.

5. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.
a) 0.5
b) 500
c) 10
d) 50

View Answer

Answer: c [Reason:] Flue gas discharge velocity through chimney of a big thermal power plant may be around 10 m/sec.

6. Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.
a) 1000
b) 4000
c) 6000
d) 8000

View Answer

Answer: b [Reason:] Calorific value of coal middling generated in coal washeries during washing of coal may be around 4000 Kcal/kg.

7. Combustion of pulverised coal as compared to that of lump coal
a) develops a non-luminous flame
b) can be done with less excess air
c) develops a low temperature flame
d) provides a lower rate of heat release

View Answer

Answer: b [Reason:] Combustion of pulverised coal as compared to that of lump coal can be done with less excess air.

8. The decrease in the atomic number is not observed in case of
a) alpha emission
b) beta emission
c) gamma emission
d) none of the mentioned

View Answer

Answer: b [Reason:] There is no change in the atomic number as the number of electrons remains the same.

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