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# Multiple choice question for engineering

## Set 1

1. The maximum number of jets, generally, employed in an impulse turbine without jet interference are
a) 2
b) 6
c) 7
d) 5

Answer: a [Reason:] The maximum number of jets, generally, employed in an impulse turbine without jet interference are 2.

2. A Francis turbine is used when the available head of water is
a) 0 to 25 m
b) 25 to 250 m
c) > 250 m
d) none of the mentioned

Answer: b [Reason:] Francis Turbine is used for high heads of water.

3. The overall efficiency of a reaction turbine is the ratio of
a) actual work available at the turbine to the energy imparted to the wheel
b) power produced by the turbine to the energy actually supplied by the turbine
c) workdone on the wheel to the energy (or head of water) actually supplied to the turbine
d) none of the mentioned

Answer: b [Reason:] The overall efficiency of a reaction turbine is the ratio of power produced by the turbine to the energy actually supplied by the turbine.

4. Manometric head, in case of a centrifugal pump, is equal to
a) Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe
b) Energy per kN at outlet of impeller – Energy per kN at inlet of impeller
c) Workdone per kN of water – Losses within the impeller
d) All of the mentioned

Answer: d [Reason:] Manometric head, in case of a centrifugal pump = Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe = Energy per kN at outlet of impeller – Energy per kN at inlet of impeller = Workdone per kN of water – Losses within the impeller.

5. The mechanical efficiency of an impulse turbine is
a) ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
b) ratio of the actual work available at the turbine to the energy imparted to the wheel
c) ratio of the Work done on the wheel to the energy of the jet
d) none of the mentioned

Answer: b [Reason:] The mechanical efficiency of an impulse turbine is ratio of the actual work available at the turbine to the energy imparted to the wheel.

6. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as
a) unit speed
b) terrific speed
c) specific velocity
d) specific speed

Answer: d [Reason:] The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as Specific Speed.

7. Geometric similarity is said to exist between the model and the prototype, if both of them
a) are equal in size and shape
b) have identical velocities
c) have identical forces
d) are identical in shape, but differ only in size

Answer: d [Reason:] Geometric similarity is said to exist between the model and the prototype, if both of them are identical in shape, but differ only in size.

8. A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the

Answer: a [Reason:] A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the manometric head.

9. Slip of a reciprocating pump is defined as the
a) sum of actual discharge and the theoretical discharge
b) ratio of actual discharge to the theoretical discharge
c) difference of theoretical discharge and the actual discharge
d) product of theoretical discharge and the actual discharge

Answer: c [Reason:] Slip of a reciprocating pump is defined as the difference of theoretical discharge and the actual discharge.

10. Multi-stage centrifugal pumps are used to
b) give high discharge
c) pump viscous fluids
d) all of the mentioned

Answer: a [Reason:] Multi-stage centrifugal pumps are used to produce high heads.

11. A hydraulic coupling belongs to the category of
a) power absorbing machines
b) energy transfer machines
c) power developing machines
d) energy generating machines

Answer: b [Reason:] A hydraulic coupling belongs to the category of energy transfer machines.

12. Discharge of a centrifugal pump is
a) inversely proportional to (diameter)2 of its impeller
b) inversely proportional to diameter of its impeller
c) directly proportional to (diameter)2 of its impeller
d) directly proportional to diameter of its impeller

Answer: a [Reason:] Discharge of a centrifugal pump is inversely proportional to (diameter)2 of its impeller.

13. Which of the following turbine is preferred for 0 to 25 m head of water?
a) Kaplan Turbine
b) Pelton Turbine
c) Francis Turbine
d) None of the mentioned

Answer: a [Reason:] Kaplan turbine is preferred for low heads of water.

## Set 2

1. Steam is generated in a _____________ boiler at a pressure above the critical point.
a) simple
b) once through
c) superficial
d) thrice through

Answer: The steam generation in a supercritical pressure cycle is in a once through boiler when the steam is heated at a pressure above the critical point.

2. Apart from feedheating, what should a plant have to obtain a gain in thermal efficiency?
a) Lubrication
b) Differential heating
c) Reheating cycles
d) Regenerative cycles

Answer: c [Reason:] To obtain a gain in thermal cycle efficiency, apart from the feedheating, there should be multiple number of reheats.

3. The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of?
a) compactness of the plant
b) simplicity of the plant
c) complexity of the plant
d) expanse of the plant

Answer: c [Reason:] The increment in thermal efficiency compared to the corresponding Subcritical cycle is gained at the expanse of complexity of the plant. Naturally, more the complexity, more this increment.

4. Which of the following needs to be incorporated to prevent the low pressure turbine exhaust wetness from being excessive?
a) Double regeneration
b) Double carnotization
c) Double reheat
d) Double cooling

Answer: c [Reason:] Incorporating double reheat is one way to prevent the low pressure turbine exhaust wetness from being excessive.

5. What is the critical point of steam generation in a “once through” boiler?
a) 221.5 bar
b) 221.4 bar
c) 221.3 bar
d) 221.2 bar

Answer: d [Reason:] Steam generation in a “once through” boiler is at the critical point of 221.2 bar.

6. In a typical layout of a 215MW reheat power plant, the feed in the boiler is at?

Answer: c [Reason:] In a typical layout of a 215MW reheat power plant, the feed in the boiler is at 238 degree Centigrade.

7. The input to the deaerator is from a __________ pressure feedwater heater.
a) high
b) low
c) medium
d) none of the mentioned

Answer: b [Reason:] The deaerator input is at low pressure feedwater heater and so the working of the deaerator comes into play.

8. The input to the low pressure feedwater heater is from?
a) Drain heater
b) Drain cooler
c) Drain pipe
d) None of the mentioned

Answer: b [Reason:] The input to the low pressure feedwater heater comes from the drain cooler which the goes to the deaerator.

## Set 3

1. The overall plant efficiencies in case of a combined cycle power generation is?
a) Low
b) High
c) Very low
d) Very high

Answer: b [Reason:] It is practically possible to attain efficiencies near to 50% in case of a combined cycle power generation.

2. The investment cost related to the combined power generation is?
a) high
b) low
c) very high
d) none of the mentioned

Answer: b [Reason:] The investment cost related to the combined power generation is. This is because only 2/3 of the total output is produced in the gas turbine.

3. What % are the investment cost in Conventional steam power plant more than those in the combined cycle plants?
a) 10
b) 20
c) 30
d) 40

Answer: c [Reason:] The investment cost in Conventional steam power plant is 30% more than those in the combined cycle plants.

4. The amount of water required as coolant for a combined cycle plant is?
a) very high
b) less
c) medium
d) none of the mentioned

Answer: b [Reason:] The amount of cooling water required is only 40-50% of the steam power plant requirement.

5. Combined cycle plants have _____________ operation flexibility.
a) high
b) low

Answer: a [Reason:] The ease of operation, i.e, the ease with which the plant can be started and stopped is the operation flexibility.

6. Installations in stages is possible in Combined Cycle Plants.
a) true
b) false

Answer: a [Reason:] Because the gas turbines go into operation much sooner than the steam plants, installations in stages is possible in Combined Cycle plants.

7. Which of these has most simple operation?
a) combined cycle plant
b) steam plant
c) both of the mentioned
d) none of the mentioned

Answer: a [Reason:] Combined cycle plant is more flexible than the steam plant and so it has the simplest operation.

8. Combustion in a Combined cycle plant has______ environmental impact?
a) serious
b) little/no
c) toxic
d) none of the mentioned

Answer: b [Reason:] As most of the processes of a combined cycle plant are degradable, so combustion in a combined cycle plant has no impact on the environment.

9. Cogeneration of heat & electricity is possible in a Combined cycle plants.
a) True
b) False

Answer: a [Reason:] One of the major advantages of a combined cycle plants is the cogeneration of heat & electricity.

10. Efficiency of Natural gas fired Combined cycle plants is more than that of coal-fired plants.
a) true
b) false

Answer: a [Reason:] As the efficiency of a combined cycle plant is high in comparison to that of steam power plant, naturally, the statement mentioned becomes true.

## Set 4

1. The relative efficiency is defined as?
a) ratio of thermal efficiency to rankine efficiency
b) ratio of brake power to the indicated power
c) ratio of heat equivalent to indicated power to the energy supplied in steam
d) product of thermal efficiency & Rankine efficiency

Answer: a [Reason:] The ratio of thermal efficiency to rankine efficiency is called Relative efficiency.

2. Lancashire boiler is?
a) stationary fire tube boiler
b) horizontal boiler
c) internally fired boiler
d) all of the mentioned

Answer: d [Reason:] Lancashire boiler is a stationary fire tube, horizontal & internally fired boiler.

3. The heat balance sheet for the boiler shows the
a) steam formed by combustion of hydrogen per kg of fuel
b) moisture present in the fuel
c) complete account of heat supplied by 1 kg of dry fuel & the heat consumed
d) all of the mentioned

Answer: c [Reason:] The heat balance sheet for the boiler shows the complete account of heat supplied by 1 kg of dry fuel & the heat consumed.

4. A compound steam engine in which piston rods of high pressure & low pressure cylinders are attached to two different crank sets at 1800 to each other, is called
a) Tandem type compound engine
c) Woolf type compound engine
d) none of the mentioned

Answer: c [Reason:] A compound steam engine in which piston rods of high pressure & low pressure cylinders are attached to two different crank sets at 1800 to each other, is called Woolf type compound engine.

5. The actual vacuum in a condenser is equal to
a) barometric pressure – actual pressure
b) barometric pressure + actual pressure
c) gauge pressure – atmospheric pressure
d) gauge pressure + atmospheric pressure

Answer: a [Reason:] The actual vacuum in a condenser is equal to barometric pressure – actual pressure.

6. The high steam and low water safety valve is used to blow off steam when the
a) steam pressure exceeds the working pressure
b) water level in the boiler becomes too low
c) none of the mentioned
d) both of the mentioned

Answer: d [Reason:] The high steam and low water safety valve is used to blow off steam when the steam pressure exceeds the working pressure & water level in the boiler becomes too low.

7. The performance of a boiler is measured by the
a) dry flue gases
b) steam formation
c) moisture in fuel
d) unburnt carbon

Answer: a [Reason:] The performance of a boiler is measured by the amount of dry flue gases exhausted.

8. Benson boiler requires
a) 2 drums
b) 3 drums
c) 0 drums
d) 1 drum

Answer: c [Reason:] Benson boiler requires no drums. It is a drum-less boiler.

9. The cylinder condensation or missing quantity may be reduced by
a) keeping the expansion ratio small in each cylinder
b) superheating the steam supplied to the engine cylinder
c) the efficient steam jacketing of the cylinder walls
d) all of the mentioned

Answer: d [Reason:] The cylinder condensation or missing quantity may be reduced by keeping the expansion ratio small, superheating the steam supplied to the engine cylinder, the efficient steam jacketing of the cylinder walls, etc.

10. In a Tandem type compound engine, the high pressure and low pressure cylinders
a) have common piston rods
b) have separate piston rods
c) are set at 90 degrees
d) are set in V-arrangement

Answer: a [Reason:] In a Tandem type compound engine, the high pressure and low pressure cylinders have common piston rods.

11. A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as
a) fusible plug
b) superheater
c) stop valve
d) blow off cork

Answer: c [Reason:] A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as Stop Valve.

12. The performance of a boiler is measured by the
a) steam produced in kg/h
b) steam produced in kg/kg of fuel burnt
c) amount of water evaporated per hour
d) all of the mentioned

Answer: d [Reason:] The performance of a boiler is measured by the rate of steam produced in kg/h, kg/kg & the amount of water evaporated per hour.

13. The high pressure and low pressure cylinders in a receiver type compound engine are regarded as having cranks
a) 180° to each other
b) 90° to each other
c) 0° to each other
d) none of the mentioned

Answer: b [Reason:] The high pressure and low pressure cylinders in a receiver type compound engine are regarded as having cranks at 90° to each other.

14. Throttle governing of steam engines is a method of controlling the engine output by varying
a) volume of intake steam
b) pressure of intake system
c) temperature of intake system
d) none of the mentioned

Answer: b [Reason:] Throttle governing of steam engines is a method of controlling the engine output by varying pressure of intake system.

15. The aim of a compound steam engine is
a) to reduce the ratio of expansion in each cylinder
b) to reduce the temperature range in each cylinder
c) to reduce the length of stroke
d) all of the mentioned

Answer: a [Reason:] The aim of a compound steam engine is to reduce the ratio of expansion in each cylinder.

## Set 5

1. Governing principle(s) of steam turbine is?
a) Nozzle control governing
b) Throttle governing
c) Bypass governing
d) All of the mentioned

Answer: d [Reason:] The various principles of Steam turbine governance are Nozzle control governing, bypass governing, throttle governing, etc.

2. Air-Preheater in a steam power plant_____________
a) Recovers the heat from the flue gases leaving the economiser.
b) Improves combustion rate.
c) Raises the temperature of the furnace gases.
d) All of the mentioned

Answer: d [Reason:] Air- preheater in a steam power plant recovers the heat from the flue gases leaving the economiser, improves combustion rate, raises temperature of the furnace gases, etc.

3. The definition of the draught system is
a) A device used to pull in air.
b) The difference between absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure.
c) The sum of the absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure.
d) A device used to pull out air

Answer: d [Reason:] The difference between absolute gas pressure at any point in a gas flow and the ambient atmospheric pressure is called Draught.

4. A condenser condenses the steam coming out from?
a) Boiler
b) Turbine
c) Economiser
d) Super heater

Answer: b [Reason:] The condensing action of a condenser begins when the steam comes out from the Turbine.

5. Water used in the steam plant is used for cooling in_______________
a) Condenser
b) Turbine only
c) Boiler tube
d) Boiler tubes and turbines

Answer: a [Reason:] The only condensing process in a steam power plant occurs in the condenser so the water used in the steam plant is used for cooling in Condenser.

6. What is use of the air pumps in the condenser?
a) Remove water
b) Air leaking in the condenser and to maintain the vacuum.
c) Maintain atmospheric pressure and the condenser.
d) Both (a) & (b)

Answer: b [Reason:] Air pumps used in the condenser are used to maintain the vacuum by letting air outside.

7. Spray ponds are used to cool the warm water coming from the condenser in ________
a) Large power plants
b) Small power plants
c) Medium power plants
d) Both medium and large power plants

Answer: b [Reason:] Spray ponds are used to cool the warm water coming from the condenser in small power plants.

8. Evaporative type of condenser has
a) Water in pipes surrounded by steam outside.
b) Steam and cooling water mixed to give the condensate.
c) Steam in pipes surrounded by water.
d) None of the mentioned

Answer: c [Reason:] Steam in pipes surrounded by water is the evaporative type condenser.

9. Due to friction between the fluid & walls of the nozzle, the expansion process is?
a) reversible
b) irreversible

Answer: d [Reason:] The friction between the walls of fluid & walls of the nozzle is irreversible & the entire process remains adiabatic.

10. The ratio of actual mass flow through the nozzle to the mass flow if the flow were isentropic is?
a) Coefficient of viscosity
b) Coefficient of velocity
c) Coefficient of discharge
d) None of the mentioned