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Multiple choice question for engineering

Set 1

1. The bearing friction includes the friction due to main bearing connecting rod bearing and other bearings.
a) True
b) False

View Answer

Answer: a

2. Bearing friction is viscous in nature and does not depends upon the oil viscosity, the speed, size and geometry of the journal.
a) True
b) False

View Answer

Answer: b [Reason:] No, actually, bearing friction is viscous in nature and depends upon the oil viscosity, the speed, size and geometry of the journal.

3. The valve gear friction losses vary with the engine design variables and no general equation is available predicting them.
a) True
b) False

View Answer

Answer: a

4. The blow by losses is the phenomenon of leakage of combustion products past the piston and piston rings from the cylinder to the crankcase.
a) True
b) False

View Answer

Answer: a

5. Blow by losses depend on the outlet pressure and compression ratio.
a) True
b) False

View Answer

Answer: b [Reason:] In fact, blow by losses depend on the inlet pressure and compression ratio.

6. Blow by losses vary as the square root of inlet pressure, and increases as the compression ratio is
a) increased
b) reduced
c) unpredictable
d) none of the mentioned

View Answer

Answer: a

7. Blow by losses are reduced as the engine speed is
a) increased
b) reduced
c) unpredictable
d) none of the mentioned

View Answer

Answer: a [Reason:] Blow by losses are indirectly proportional to engine speed and it is reduced as the engine speed is increased.

8. A rise in cooling water temperature ____________ engine friction through its effect on oil viscosity.
a) increases
b) reduces
c) unpredictable
d) none of the mentioned

View Answer

Answer: b

9. Higher the oil viscosity ____________ is the friction loss.
a) lower
b) greater
c) unpredictable
d) none of the mentioned

View Answer

Answer: b [Reason:] Viscosity is proportional to friction loss, so higher the oil viscosity greater is the friction loss.

10. As the load increases the maxim,um pressure in the cylinder has a tendency to increase slightly.
a) True
b) False

View Answer

Answer: a

Set 2

1. ____________ is the transfer of heat from one part of a substance to another part of the same substance.
a) Convection
b) Conduction
c) Radiation
d) None of the mentioned

View Answer

Answer: b [Reason:] Conduction is defined as the transfer of heat from one part of a substance to another part of the same substance while convection is defined as the transfer of heat within a fluid by mixing of one portion of fluid with another.

2. ____________ is the transfer of heat within a fluid by mixing of one portion of fluid with another.
a) Convection
b) Conduction
c) Radiation
d) None of the mentioned

View Answer

Answer: a [Reason:] Convection is defined as the transfer of heat within a fluid by mixing of one portion of fluid with another while conduction is defined as the transfer of heat from one part of a substance to another part of the same substance.

3. ____________ convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.
a) Forced
b) Natural
c) Unpredictable.
d) None of the mentioned

View Answer

Answer: b

4. In natural convection, the denser portions of the fluid move downward because of the greater force of gravity, as compared with the force on the less dense.
a) True
b) False

View Answer

Answer: a

5. When the work is done to blow or pump the fluid, it is said to be ____________ convection.
a) natural
b) forced
c) unpredictable
d) none of the mentioned

View Answer

Answer: b [Reason:] When the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

6. ____________ is the transfer of heat through space or matter by means other than conduction or convection.
a) Forced
b) Natural
c) Radiation
d) None of the mentioned

View Answer

Answer: c [Reason:] Radiation is the transfer of heat through space or matter by means other than conduction or convection and when the work is done to blow or pump the fluid, it is said to be forced convection while natural convection occurs when the fluid circulates by virtue of the natural differences in densities of hot and cold fluids.

7. In case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.
a) True
b) False

View Answer

Answer: a [Reason:] Yes, in case of air cooling, the boundary layer as on the gas side offers great resistance, but the effect of this is compensated largely by providing more surface areas by way of cooling pins.

8. In case of water cooling, there no boundary layer of the liquid coolant on the outside of the cylinder wall.
a) True
b) False

View Answer

Answer: b [Reason:] Actually, in case of water cooling, there is also a boundary layer of the liquid coolant on the outside of the cylinder wall.

9. When the spark advance is same as the optimum value the heat rejected to cooling system is increased.
a) True
b) False

View Answer

Answer: b [Reason:] In fact, when the spark advance is different from the optimum value the heat rejected to cooling system is increased.

10. Gas temperature remain at a higher average with increased speed.
a) True
b) False

View Answer

Answer: a

Set 3

1. The main aims of an engine management system is to achieve
a) high reliability and durability with lowest possible initial cost
b) high power output and torque
c) low levels of gaseous and particulate emissions
d) all of the mentioned

View Answer

Answer: d [Reason:] The main aims of an engine management system is to achieve a) high reliability and durability with lowest possible initial cost b) high power output and torque c) low levels of gaseous and particulate emissions d) low fuel consumption e) low noise levels and vibrations.

2. The important parameters in a gasoline engine that can be controlled are
a) air-fuel ratio
b) mixture distribution between cylinders
c) ignition timing
d) all of the mentioned

View Answer

Answer: d [Reason:] The important parameters in a gasoline engine that can be controlled are a) air-fuel ratio b) mixture distribution between cylinders c) ignition timing d) injection timing of the fuel e) idle speed.

3. Hall effect pickup use
a) inductive transducers
b) potentiometers
c) thermistors
d) semiconductors

View Answer

Answer: d [Reason:] Hall effect pickup is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing application and thus it uses semiconductor.

4. LVDT is used to measure
a) crank angle
b) engine speed
c) large displacements
d) gas temperature

View Answer

Answer: c [Reason:] To measure large displacements, LVDT is used.

5. The disadvantage of the piezoelectric pressure pickup is that
a) it can only give pressure difference
b) it can measure only low pressure
c) it is not suitable for dynamic measurement
d) has too much sensitivity

View Answer

Answer: a [Reason:] By using piezoelectric pressure pickup only the pressure difference can be measured and not the low pressure.

6. Thermistors are desirable because of their
a) linear output
b) large temperature coefficient
c) suitability for high temperature
d) none of the mentioned

View Answer

Answer: b [Reason:] Only thermistors have the property to give large temperature coefficients.

7. Seebeck effect is used in
a) thermistors
b) thermocouples
c) rtd
d) hot-wire sensor

View Answer

Answer: b [Reason:] Seebeck effect is a property in thermocouples and not in thermistors and RTD.

8. Hot-wire sensors are used for measurement of
a) temperature
b) pressure
c) mass flow rate
d) smoke intensity

View Answer

Answer: c [Reason:] Only mass flow rate is measured by using hot-wire sensors.

9. Knock sensors use
a) thermistors
b) thermocouples
c) piezoelectric pickup
d) flap type sensors

View Answer

Answer: c [Reason:] In piezoelectric pickup knock sensors are used while seebeck effect is used in thermocouples.

10. Catalytic converters use lambda sensors to keep
a) exhaust temperature constant
b) exhaust pressure constant
c) excess air ratio within a range
d) flow rate of air constant

View Answer

Answer: c [Reason:] Only lambda sensors are used in catalytic converters to keep excess air ratio within a range.

Set 4

1. For which of the following engines a prony brake is used to measure brake power?
a) single cylinder engine
b) low speed engine
c) low power engine
d) variable speed engine

View Answer

Answer: d [Reason:] Prony brake is used to measure brake power of variable speed engines.

2. What does scavenging air mean?
a) Burnt air containing combustion products
b) Air sent under compression
c) Forced air for cooling the engine cylinder
d) Air used for forcing the burnt gases out of cylinder during the exhaust period

View Answer

Answer: d [Reason:] Scavenging air is defined as the air used for forcing the burnt gases out of cylinder during the exhaust period.

3. ____________ is the basic requirement of a good combustion chamber.
a) Low volumetric efficiency
b) High compression ratio
c) Low compression ratio
d) High power output and high thermal efficiency

View Answer

Answer: d [Reason:] The basic requirement of a good combustion chamber are: a) High power output b) High thermal efficiency and low specific fuel consumption c) smooth engine operation d) reduced exhaust pollutants.

4. ____________ is the method of governing used in petrol engine.
a) Quality governing
b) Hit and mass governing
c) Quantity governing
d) All of the mentioned

View Answer

Answer: a [Reason:] Quality governing is generally used in petrol engines as the quantity of air -fuel mixture flowing into the cylinder is varied accordingly and this may be done by decreasing the lift of the inlet valve or by throttling the mixture before it is made to enter the engine cylinder.

5. Hunting occurs due to which of the following?
a) Faulty governor
b) Poor control by the governor
c) Over control by the governor
d) Bad engine design

View Answer

Answer: b [Reason:] Hunting occurs due to load variation and this is only when the governor is not controlled properly.

6. Maximum torque is generated by an engine when
a) it runs at lowest speed
b) it develops maximum power
c) it consumes maximum fuel
d) it runs at maximum speed

View Answer

Answer: a [Reason:] Maximum torque is generated by an engine when it runs at lowest speed while maximum power is developed when the engine rums at its maximum speed.

7. With an increase of the number of cylinders in a multicylinder engine the power to weight ratio
a) decreases
b) increases
c) remains unaffected
d) none of the mentioned

View Answer

Answer: c [Reason:] The power to weight ratio remains unaffected even after if the number of cylinders in a multicylinder is increases because as the number of cylinders increases, torque is smoother and less flywheel mass is needed.

8. Radiator tubes are generally made of
a) cast iron
b) steel
c) plastics
d) brass

View Answer

Answer: d [Reason:] Brass is used to make radiator pipes due to it heat resistance capacities.

9. Automobile gears are generally made of
a) cast iron
b) stainless steel
c) alloy steel
d) mild steel

View Answer

Answer: c [Reason:] Steel mixed with copper, zinc and tin is used to make gears in automobiles.

10. ____________ is used to check the state of charge of a battery.
a) Battery charger
b) Hygrometer
c) Hydrometer
d) Battery eliminator

View Answer

Answer: a [Reason:] Battery charger is used to check the state of charge of a battery while hygrometer is used to check the air humidity and hydrometer is used to check the specific gravity.

Set 5

1. The thermal efficiency of a petrol engine is ____________ as compared to diesel engine.
a) same
b) less
c) more
d) none of the mentioned

View Answer

Answer: b

2. The mean effective pressure of a diesel engine having fixed compression ratio will ____________ if cut off ratio decreases.
a) increase
b) decrease
c) remain same
d) none of the mentioned

View Answer

Answer: b

3. The indicated mean effective pressure of an engine is obtained from the indicator diagram drawn with the help of an engine indicator.
a) True
b) False

View Answer

Answer: a

4. The power actually developed by the engine cylinder of an I.C. engine is known as
a) theoretical power
b) actual power
c) indicated power
d) none of the mentioned

View Answer

Answer: c

5. Number of working strokes per min. for a two stroke cycle engine are ____________ the speed of the engine in r.p.m.
a) equal to
b) one-half
c) twice
d) four-times

View Answer

Answer: a [Reason:] Number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in r.p.m while number of working strokes per min. for a four stroke cycle engine are one half the speed of the engine in r.p.m.

6. Number of working strokes per min. for a four stroke cycle engine are ____________ the speed of the engine in r.p.m.
a) equal to
b) one-half
c) twice
d) four-times

View Answer

Answer: b [Reason:] Number of working strokes per min. for a four stroke cycle engine are one half the speed of the engine in r.p.m. while number of working strokes per min. for a two stroke cycle engine are equal to the speed of the engine in r.p.m.

7. In a petrol engine, the mixture has the lowest pressure at the
a) beginning of suction stroke
b) end of suction stroke
c) end of compression stroke
d) none of the mentioned

View Answer

Answer: b

8. In compression ignition engines, swirl denotes a
a) haphazard motion of the gases in the chamber
b) rotary motion of the gases in the chamber
c) radial motion of the gases in the chamber
d) none of the mentioned

View Answer

Answer: b

9. The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to
a) inject fuel in a chamber of high pressure at the end of compression stroke
b) inject fuel at a high velocity to facilitate atomization
c) ensure that penetration is not high
d) all of the mentioned

View Answer

Answer: d [Reason:] The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to a) inject fuel in a chamber of high pressure at the end of compression stroke. b) inject fuel at a high velocity to facilitate atomization. c) ensure that penetration is not high.

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