question_answer 1)
Consider the following statements regarding the advantages of fuel injection over carburetion in S.I. engines:
1. Higher power output and increased volumetric efficiency. 2. Simple and inexpensive injection equipment. 3. Longer life of injection equipment. 4. Less knocking and reduced tendency for back-fire. Select the correct answer using the codes given below:
Codes:
A)
1, 2 and 3 done
clear
B)
1, 2 and 4 done
clear
C)
2 and 3 done
clear
D)
1 and 4 done
clear
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question_answer 2)
Match List I with List II and select the correct answer using the codes given below the lists:
List-I (Elements of a complete carburettor) List-II (Rich-mixture requirement) A. Idling system 1. To compensate for dilution of charge B. Economiser 2. Fore cold starting C. Acceleration pump 3. For meeting maximum power range of operation D Choke 4. For meeting rapid opening of throttle
Codes:
A)
A\[\to \]1, B\[\to \]2, C\[\to \]3, D\[\to \]4 done
clear
B)
A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 done
clear
C)
A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 done
clear
D)
A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done
clear
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question_answer 3)
Match List I with List II and select the correct answer using the codes given below the lists:
List-I (S.I. Engine Problem) List-II (Characteristic of fuel responsible for the problem) A. Cold starting 1. Front end volatility B. Carburettor icing 2. Mid-range volatility C. Crankcase dilutions 3. Tail end volatility
Codes:
A)
A\[\to \]1, B\[\to \]2, C\[\to \]3 done
clear
B)
A\[\to \]1, B\[\to \]3, C\[\to \]2 done
clear
C)
A\[\to \]2, B\[\to \]3, C\[\to \]1 done
clear
D)
A\[\to \]3, B\[\to \]1, C\[\to \]2 done
clear
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question_answer 4)
Besides mean effective pressure, the data needed for determining the indicated power of an engine would include:
A)
Piston diameter, length of stroke and calorific value of fuel done
clear
B)
Piston diameter, specific fuel consumption and calorific value of fuel done
clear
C)
Piston diameter, length of stroke and speed of rotation done
clear
D)
Specific fuel consumption, speed of rotation and torque done
clear
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question_answer 5)
For a typical automobile C.I engine, for conditions of increasing engine speed match List I with List II and select the correct answer using codes given below the lists:
List-I (Performance parameter) List-II (Tendency, qualitatively) A. Power output 1. Increasing and then decreasing B. Torque 2. Decreasing and then increasing C. Brake specific fuel consumption 3. Increasing throughout the range 4. Decreasing throughout the range
Codes:
A)
A\[\to \]1, B\[\to \]2, C\[\to \]3 done
clear
B)
A\[\to \]1, B\[\to \]4, C\[\to \]3 done
clear
C)
A\[\to \]2, B\[\to \]3, C\[\to \]4 done
clear
D)
A\[\to \]3, B\[\to \]1, C\[\to \]2 done
clear
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question_answer 6)
Consider the following statements:
I. The performance of an S.I. engine can be improved by increasing the compression ratio. II. Fuels of higher octane number can be employed at higher compression ratio.
Of these statements
A)
Both I and II are true done
clear
B)
Both I and II are false done
clear
C)
I is true but II is false done
clear
D)
I is false but II is true done
clear
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question_answer 7)
Match List I with List II and select the correct answer using the codes given below the lists:
List-I (Name of propellant) List-II (Type of propellant) A. Nitric acid 1. Fuel B. Hydrogen 2. Monopropellant C. Fuming nitric acid hydrazine 3. Oxidizer D. Methyl nitrate-methyl alcohol 4. Compounded liquid mono propellant 5. Hypergolic propellant
Codes:
A)
A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]5 done
clear
B)
A\[\to \]1, B\[\to \]2, C\[\to \]5, D\[\to \]4 done
clear
C)
A\[\to \]3, B\[\to \]1, C\[\to \]5, D\[\to \]4 done
clear
D)
A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]5 done
clear
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question_answer 8)
The object of providing masked inlet valve in the air passage of compression-ignition engines is to
A)
Enhance flow late done
clear
B)
Control air flow done
clear
C)
Induce primary swirl done
clear
D)
Induce secondary turbulence done
clear
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question_answer 9)
Which one of the following events would reduce the volumetric, efficiency of a vertical compression ignition engine?
A)
Intel valve closing after bottom head Centre done
clear
B)
Inlet valve closing before bottom dead Centre done
clear
C)
Inlet valve opening top dead Centre done
clear
D)
Exhaust valve closing after top dead Centre done
clear
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question_answer 10)
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to:
A)
Increase maximum pressure and maximum temperature. done
clear
B)
Reduce maximum pressure and maximum temperature. done
clear
C)
Increase maximum pressure and decrease maximum temperature. done
clear
D)
Decrease maximum pressure and Increase maximum temperature. done
clear
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question_answer 11)
For the same maximum pressure and heat input:
A)
The exhaust temperature of petrol engine is more than that of diesel engine done
clear
B)
The exhaust temperature of diesel engine is more than that of petrol engine done
clear
C)
The exhaust temperature of dual cycle engine is less than that of diesel engine done
clear
D)
The exhaust temperature of dual cycle engine is more than that of petrol engine done
clear
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question_answer 12)
In Orsat apparatus:
A)
Carbon dioxide is absorbed in cuprous chloride done
clear
B)
Carbon monoxide is absorbed in caustic potash solution done
clear
C)
Oxygen is absorbed in pyrogallic acid done
clear
D)
Nitrogen is absorbed in hot nickel chrome compound done
clear
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question_answer 13)
In solid propellants rockets, ammonium picrate is usually added as:
A)
An additive done
clear
B)
An inhibitor done
clear
C)
A darkening agent done
clear
D)
a plasticizer done
clear
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question_answer 14)
A turbo prop is preferred to turbo jet because:
A)
It has high propulsive efficiency at high speeds done
clear
B)
It can fly at supersonic speeds done
clear
C)
It can fly at high elevations done
clear
D)
It has high power for take off done
clear
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question_answer 15)
The air fuel ratio for idling speed of an automobile petrol engine is closer to:
A)
10 : 1 done
clear
B)
15 : 1 done
clear
C)
17 : 1 done
clear
D)
21 : 1 done
clear
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question_answer 16)
Which of the following statements is "true"?
A)
The term "KNOCK" is used for on identical phenomenon in a spark ignition and compression ignition engine done
clear
B)
"KNOCK" is a term associated with a phenomeno a taking place in the early part of combustion in a spark ignition engine done
clear
C)
"KNOCK" is a term associated with a phenomenon taking place in the early part of combustion in a spark ignition engine and the later part of combustion in a compression ignition engine done
clear
D)
None of the above done
clear
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question_answer 17)
The essential function of the carburettor in a spark ignition engine is to:
A)
Meter the fuel into air stream and amount dictated by the load and speed done
clear
B)
Bring about mixing of air and fuel to get a homogeneous mixture done
clear
C)
Vaporize the fuel done
clear
D)
Distribute fuel uniformly to all cylinders in a multi-cylinder engine and also vaporize it. done
clear
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question_answer 18)
Match List I with List II and select the correct answer using the codes given below the lists:
List-I List-II A. Pre-combustion chamber 1. Compression swirl B. Turbulent chamber 2. Masked inlet valve C. Open combustion chamber 3. Spark ignition D. F-head combustion chamber 4. Combustion induced swirl 5. M-chamber
Codes:
A)
A\[\to \]4, B\[\to \]5, C\[\to \]3, D\[\to \]2 done
clear
B)
A\[\to \]1, B\[\to \]3, C\[\to \]5, D\[\to \]2 done
clear
C)
A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]5 done
clear
D)
A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done
clear
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question_answer 19)
Consider the following statements comparing I.C. engines and gas turbines:
1. Gas turbines are simple, compact and light in weight. 2. Complete expansion of working substance is possible in I.C. engines and not in gas turbines. 3. There is flexibility in the design of different components of gas turbines as different processes take place in different components. 4. Even low grade fuels can be burnt in gas turbines.
Of these statement:
A)
1, 2 and 3 are correct done
clear
B)
1, 3 and 4 and correct done
clear
C)
2, 3 and 4 are correct done
clear
D)
1, 2 and 4 are correct done
clear
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question_answer 20)
Which of the following factors increase detonation in the SI engine?
1. Increase spark advance. 2. Increased speed. 3. Increased air-fuel ratio beyond stoichiometric strength. 4. Increased compression ratio. Select the correct answer using the codes given below:
Codes:
A)
1 and 3 done
clear
B)
2 and 4 done
clear
C)
1, 2 and 4 done
clear
D)
1 and 4 done
clear
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question_answer 21)
Reference fuels for knock rating of SI engine fuels would include:
A)
Iso-octane and alpha-methyl naphthalene. done
clear
B)
Normal octane and aniline done
clear
C)
Iso-octane and n-hexane done
clear
D)
n-heptane and is-octane done
clear
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question_answer 22)
Consider the following measures:
1. Increasing the compression ratio. 2. Increasing the intake air temperature. 3. Increasing the length to diameter ratio of the cylinder. 4. Increasing the engine speed.
The measures necessary to reduce the tendency to knock in CI engines would include:
A)
1, 2 and 3 done
clear
B)
1, 2 and 4 done
clear
C)
1, 3 and 4 done
clear
D)
2, 3 and 4 done
clear
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question_answer 23)
Match List I with List II and select the correct answer using the codes given below the Lists:
List-I (Operating condition) List-II (Approximate air fuel ratio) A. Idling 1. 16 B. Part load operation 2. 10 C. Full load 3. 12.5 D. Cold start 4. 3
Codes:
A)
A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 done
clear
B)
A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 done
clear
C)
A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]3 done
clear
D)
A\[\to \]1, B\[\to \]2, C\[\to \]3, D\[\to \]4 done
clear
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question_answer 24)
Generally, in Bosch type fuel injection pumps, the quantity of fuel is increased or decreased with change in load, due to change in:
A)
Timing of start of fuel injection done
clear
B)
Timing of end fuel injection done
clear
C)
Injection pressure of fuel done
clear
D)
Velocity of flow of fuel done
clear
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question_answer 25)
If the approximate average mean pressures during induction, compression, power and exhaust strokes of an internal combustion engine are respectively \[\text{15}\,\,\text{k}\,\text{N/}{{\text{m}}^{\text{2}}}\] below atmosphere 200\[k\,\text{N/m}\] above atmosphere, \[\text{1000}\,\,\text{k}\,\text{N/}{{\text{m}}^{\text{2}}}\] above atmosphere and \[20\,\,\text{N/}{{\text{m}}^{\text{2}}}\] above atmosphere, then the resultant mean effective pressure, in \[k\,\text{N/}{{\text{m}}^{\text{2}}},\] is:
A)
765 done
clear
B)
795 done
clear
C)
800 done
clear
D)
805 done
clear
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question_answer 26)
An automatic expansion valve is required to maintain constant:
A)
Pressure in the evaporator done
clear
B)
Temperature in the freezer done
clear
C)
Pressure in the liquid line done
clear
D)
Temperature in the condenser done
clear
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question_answer 27)
Which one of following quantities is assumed constant for an internal combustion engine while estimating its friction power by extrapolation through Willan's line?
A)
Brake thermal efficiency done
clear
B)
Indicated thermal efficiency done
clear
C)
Mechanical efficiency done
clear
D)
Volumetric efficiency done
clear
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question_answer 28)
Excessive pressure drop in liquid line in a refrigerating system causes:
A)
High condenser pressure done
clear
B)
Flashing of the liquid refrigerant done
clear
C)
Higher evaporator pressure done
clear
D)
Under cooling of the liquid refrigerant done
clear
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question_answer 29)
If V is the jet velocity Vo is the Vehicle velocity, the propulsive efficiency of a rocket is given by:
A)
\[\frac{2\,\left( {{\text{V}}_{\text{0}}}\text{/}{{\text{V}}_{\text{1}}} \right)}{1+\left( \frac{{{V}_{0}}}{{{V}_{1}}} \right)}\] done
clear
B)
\[\frac{\left( {{\text{V}}_{\text{0}}}\text{/}{{\text{V}}_{\text{1}}} \right)}{1+{{\left( \frac{{{V}_{0}}}{{{V}_{1}}} \right)}^{2}}}\] done
clear
C)
\[\frac{{{V}_{0}}}{{{V}_{0}}+{{V}_{1}}}\] done
clear
D)
\[\frac{{{V}_{1}}}{{{V}_{0}}+{{V}_{1}}}\] done
clear
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question_answer 30)
Match List I with List II in respect of a chemical rocket engine and select the correct answer using the codes given below the List:
List-I List-II A. Ethyl alcohol 1. Liquid oxidizer B. Nitrocellulose 2. Liquid fuel C. Ammonium perchlorate 3. Solid oxidizer D. Hydrogen peroxide 4. Solid fuel
Codes:
A)
A\[\to \]1, B\[\to \]3, C\[\to \]2, D\[\to \]4 done
clear
B)
A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 done
clear
C)
A\[\to \]2, B\[\to \]4, C\[\to \]3, D\[\to \]1 done
clear
D)
A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done
clear
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question_answer 31)
Match List I with List II and select the correct answer using the codes given below the lists:
List-I (Operating mode of SI engine) List-II (Appropriate air-fuel ratio) A. Idling 1. 125 B. Cold starting 2. 9.0 C. Cruising 3. 16.0 D Maximum power 4. 22.0 5. 3.0
Codes:
A)
A\[\to \]2, B\[\to \]4, C\[\to \]5, D\[\to \]1 done
clear
B)
A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 done
clear
C)
A\[\to \]5, B\[\to \]2, C\[\to \]1, D\[\to \]3 done
clear
D)
A\[\to \]2, B\[\to \]5, C\[\to \]3, D\[\to \]1 done
clear
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question_answer 32)
A gas engine has a swept volume of 300 cc and clearance volume of 25 cc. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. What is the volume of the mixture taken in per Stroke?
A)
248 cc done
clear
B)
252 cc done
clear
C)
264 cc done
clear
D)
286 cc done
clear
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question_answer 33)
Knocking in the SI engine decreases in which one of the following orders of combustion chamber designs?
A)
F head, L head, I head done
clear
B)
T head, L head, F head done
clear
C)
I head, T head, F head done
clear
D)
F head, I head, T head. done
clear
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question_answer 34)
The two reference fuels used for cetane rating are:
A)
Cetane and isooctane done
clear
B)
Cetane and tetraethyl lead done
clear
C)
Cetane and n-heptane done
clear
D)
Cetane and a-methyl naphthalene. done
clear
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question_answer 35)
Match List I with List II, in respect of SI engines, and select the correct answer by using given below the list:
List-I List-II A. Highest useful compression ratio 1. Ignitable mixture B. Dopes 2. Knock rating, of fuels C. Limiting mixture strength 3. Detonation D. Delay period 4. Chain of chemical reactions in combustion chamber
Codes:
A)
A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]4 done
clear
B)
A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4 done
clear
C)
A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 done
clear
D)
A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done
clear
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question_answer 36)
By higher octane number of SI fuel, it is meant that the fuel has:
A)
Higher heating value done
clear
B)
Higher flash point done
clear
C)
Lower volatility done
clear
D)
Longer ignition delay done
clear
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question_answer 37)
Witch of the following factors would increase the probability of knock in the CI engines?
1. Long ignition delay of fuel 2. Low self-ignition temperature of fuel 3. Low volatility of fuel Select the correct answer using the codes given below:
Codes:
A)
1, 2 and 3 done
clear
B)
1 and 2 done
clear
C)
1 and 3 done
clear
D)
2 and 3 done
clear
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question_answer 38)
Use of hermetically sealed compressor in a vapour compression refrigeration system results in:
A)
Decrease in energy consumption done
clear
B)
Increase in energy consumption done
clear
C)
Increase in COP done
clear
D)
Increase in pressure ratio done
clear
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question_answer 39)
The correct sequence of the decreasing order of brake thermal efficiency of the three given basic type of IC engines is:
A)
4 stroke CI engine, 4 stroke SI engine. 2 stroke SI engine done
clear
B)
4 stroke SI engine, 4 stroke CI engine, 2 stroke SI engine done
clear
C)
4 stroke CI engine, 2 stroke SI engine. 4 stroke SI engine done
clear
D)
2 stroke SI engine, 4 stroke SI engine, 4 stroke CI engine. done
clear
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question_answer 40)
Keeping other parameters constant brake power diesel engine can he increased by:
A)
Decreasing the density of intake air done
clear
B)
Increasing the temperature of intake air done
clear
C)
Increasing the pressure of intake air done
clear
D)
Decreasing the pressure of intake air. done
clear
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question_answer 41)
The method of determination of indicated power of multi-cylinder SI engine is by the use of:
A)
Morse test done
clear
B)
Prony brake test done
clear
C)
Motorist test done
clear
D)
Heat balance test done
clear
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question_answer 42)
Consider the following statements: As compared to turboprop, a turbojet
1. Can operate at higher altitudes 2. Can operate at higher flight velocities 3. Is more fuel efficient at lower speeds
Of these statements:
A)
1, 2 and 3 are correct done
clear
B)
1 and 2 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1 and 3 are correct. done
clear
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question_answer 43)
Propulsion efficiency of a jet engine is given by(where u is flight velocity and V is jet velocity relative to aircraft):
A)
\[\text{2}\,\text{u/}\left( \text{V}\,\,-\,\,\text{u} \right)\] done
clear
B)
\[\left( \text{V}\,\,\text{+}\,\,\text{u} \right)\text{/2}\,\text{u}\] done
clear
C)
\[\text{2}\,\text{u/}\left( \text{V}\,\,\text{+}\,\,\text{u} \right)\] done
clear
D)
\[\left( \text{V}\,\,-\,\,\text{u} \right)\text{/2}\,\text{u}\] done
clear
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question_answer 44)
In the Orsat flue gas analyser, ammonia Cal cuprous chloride is used to absorb:
A)
\[C{{O}_{2}}\] done
clear
B)
CO done
clear
C)
\[{{O}_{2}}\] done
clear
D)
\[{{N}_{2}}\] done
clear
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question_answer 45)
List I gives the different terms related to combustion while List II gives the outcome of the events that follow. Match List I with List II and select the correct answer.
List-I List-II A. Association 1. Pseudo shock B. Dissociation 2. Knock C. Flame front 3. Endothermic D. Abnormal combustion 4. Exothermic
Codes:
A)
A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2 done
clear
B)
A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 done
clear
C)
A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done
clear
D)
A\[\to \]4, B\[\to \]3, C\[\to \]2, D\[\to \]1 done
clear
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question_answer 46)
Which one of the following engines will have heavier flywheel than the remaining ones?
A)
40 HP. four-stroke petrol engine running at 1500 rmp. done
clear
B)
40 H.P. two-stroke petrol engine running at 1500 rmp. done
clear
C)
40 H.P. two-stroke diesel engine running at 750 rmp. done
clear
D)
40 H.P. four-stroke diesel engine running at 750 rmp. done
clear
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question_answer 47)
Consider the following statements: Knock in the SI engine can be reduced by
1. Supercharging 2. Retarding the spark. 3. Using a fuel of long straight chain structure. 4. Increasing the engine speed.
Of these statement:
A)
1 and 2 are correct done
clear
B)
2 and 3 are correct done
clear
C)
1, 3 and 4 are correct done
clear
D)
2 and 4 are correct done
clear
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question_answer 48)
Consider the following statements: The injector nozzle of a CI engine is required to inject fuel at a sufficiently high pressure in order to
1. be able to inject fuel in a chamber of high pressure at the end of the compression stroke. 2. Inject fuel at high velocity to facilitate atomization. 3. Ensure that penetration is not high.
Of the above statements
A)
1 and 2 are correct done
clear
B)
1 and 3 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1, 2 and 4 are correct done
clear
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question_answer 49)
Match List I with List II select the correct answer
List-I (SI engine operating mode) List-II (Desired air-fuel ratio) A. Idling 1. 13.0 B. Cold starting 2. 4.0 C. Cruising 3. 16.0 D. Full throttle 4. 9.0
Codes:
A)
A\[\to \]4, B\[\to \]3, C\[\to \]2, D\[\to \]1 done
clear
B)
A\[\to \]2, B\[\to \]4, C\[\to \]1, D\[\to \]3 done
clear
C)
A\[\to \]4, B\[\to \]2, C\[\to \]1, D\[\to \]3 done
clear
D)
A\[\to \]2, B\[\to \]4, C\[\to \]3, D\[\to \]1 done
clear
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question_answer 50)
Compensating jet in carburettor supplies almost constant amount of petrol at all speeds because:
A)
The jet area is automatically varied depending on the suction. done
clear
B)
The flow from the main jet is diverted to the compensating jet with increase in speed. done
clear
C)
The diameter of the jet is constant and the discharge coefficient is invariant. done
clear
D)
The flow is produced due to the static heal in the float Chamber. done
clear
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question_answer 51)
In the context of performance evaluation of I.C. Engine, match List I with List II and select the correct answer
List-I (Parameter) List-II (Equipment for measurement) A. Brake power(B.H.P.) 1. Bomb calorimeter B. Engine speed 2. Electrical tachometer C. Calorific value of fuel 3. Hydraulic dynamometer D. Exhaust emissions 4. Flame ionisation detector
Codes:
A)
A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4 done
clear
B)
A\[\to \]4, B\[\to \]2, C\[\to \]1, D\[\to \]3 done
clear
C)
A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4 done
clear
D)
A\[\to \]2, B\[\to \]3, C\[\to \]4, D\[\to \]1 done
clear
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question_answer 52)
Consider the following statements:
In open cycle turbo jet engines used in military aircraft, reheating the exhaust gas from the turbine by burning more fuel is used to increase. 1. Thrust. 2. The efficiency of engine. 3. The range of aircraft.
Of these statements:
A)
1 and 3 are correct done
clear
B)
1 and 2 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1, 2 and 3 are correct. done
clear
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question_answer 53)
In a turbo-jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in:
A)
Turbine blades, which is essentially an isentropic process. done
clear
B)
Turbine blades, which is polytropic process. done
clear
C)
Exit nozzle, which is essentially an isentropic process. done
clear
D)
Exit nozzle, which is a constant volume process. done
clear
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question_answer 54)
Consider the following statements relating to rocket engines:
1. The combustion chamber in a rocket engine is directly analogous to the reservoir of a supersonic wind tunnel. 2. Stagnation conditions exist at the combustion chamber. 3. The exit velocities of exhaust gases are much higher than those in jet engines. 4. Efficiency of rocket engines is higher than that of jet engines.
Of these statements:
A)
1, 3 and 4 are correct done
clear
B)
1, 3 and 4 are correct done
clear
C)
1, 2 and 3 are correct done
clear
D)
1 and 4 are correct done
clear
View Solution play_arrow
question_answer 55)
only rocket engines can be propelled to 'SPACE' because:
A)
They can generate very high thrust. done
clear
B)
They have high propulsion efficiency. done
clear
C)
These engines can work on several fuels. done
clear
D)
They are not air-breathing engines. done
clear
View Solution play_arrow
question_answer 56)
Items given in List I and List II pertain to gas analysis. Match List I with List II and select the correct answer.
List-I List-II A. \[C{{O}_{2}}\] 1. Alkaline pyrogallol B. Orsat apparatus 2. KOH solution C. CO 3. Wet analysis D. \[{{O}_{2}}\] 4. Ammonia-calcurprous chloride 5. Dry analysis
Codes:
A)
A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]4 done
clear
B)
A\[\to \]1, B\[\to \]3, C\[\to \]2, D\[\to \]4 done
clear
C)
A\[\to \]1, B\[\to \]5, C\[\to \]4, D\[\to \]2 done
clear
D)
A\[\to \]2, B\[\to \]5, C\[\to \]4, D\[\to \]1 done
clear
View Solution play_arrow
question_answer 57)
Which of the following factors are responsible formation of \[N{{O}_{X}}\] in spark ignition engine combustion:
1. Incomplete combustion 2. High temperature 3. Availability of answer.
A)
2 and 3 done
clear
B)
1 and 2 done
clear
C)
1 and 3 done
clear
D)
1, 2 and 3 done
clear
View Solution play_arrow
question_answer 58)
The presence of nitrogen in the products of combustion ensures that:
A)
Complete combustion of fuel takes place done
clear
B)
Incomplete combustion of fuel occurs done
clear
C)
Dry products of combustion are analysed done
clear
D)
Air is used for the combustion done
clear
View Solution play_arrow
question_answer 59)
For maximum specific output of a constant volume cycle (Otto cycle):
A)
The working fluid should he air done
clear
B)
The speed should he high done
clear
C)
Suction temperature should be high done
clear
D)
Temperature of the working fluid at the end of compression and expansion should be equal done
clear
View Solution play_arrow
question_answer 60)
A two-stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two-stroke engine will:
A)
Be twice that of the four-stroke engine done
clear
B)
Be half that of the four-stroke engine done
clear
C)
Be the same as that of the four-stroke done
clear
D)
Depend upon whether it is a C.I. or S.I. engine done
clear
View Solution play_arrow
question_answer 61)
For same power output and same compression ratio, as compared to two-stroke engines, four-stroke S.I. engines have:
A)
Higher fuel consumption done
clear
B)
Lower thermal efficiency done
clear
C)
Higher exhaust temperatures done
clear
D)
Higher thermal efficiency done
clear
View Solution play_arrow
question_answer 62)
In a SI Engine, which one of the following is the correct order of the fuels with increasing detonation tendency?
A)
Paraffins, Olefins, Naphthenes, Aeromatics done
clear
B)
Aeromatics, Naphthenes, Paraffins, Olefins done
clear
C)
Naphthenes, Olefins, Aeromatics, Paraffins done
clear
D)
Aeromatics, Naphthenes, Olefins, Paraffins done
clear
View Solution play_arrow
question_answer 63)
Consider the following statements: Detonation in the S.I. engine can be suppressed by
1. Retarding the spark timing 2. Increasing the engine speed. 3. Using 10% rich mixture.
Of these statements:
A)
1 and 3 are correct done
clear
B)
2 and 3 are correct done
clear
C)
1, 2 and 3 are correct done
clear
D)
1 and 2 are correct done
clear
View Solution play_arrow
question_answer 64)
The pipes and fittings in an ammonia refrigeration system should be made of:
A)
Cast street or wrought iron done
clear
B)
Aluminum done
clear
C)
Naval brass done
clear
D)
Copper done
clear
View Solution play_arrow
question_answer 65)
A sample of moist air is at a temperature T and relative humidity 50%. A part of the moisture is removed adiabatically by using an absorbent. If the heat of adsorption is negligible, the resulting air will have the same:
A)
Dry bulb temperature but a lower wet bulb temperature done
clear
B)
Wet bulb temperature but a higher dry bulb temperature done
clear
C)
Dry bulb temperature but a higher dry bulb temperature done
clear
D)
Wet bulb temperature but a lower dry bulb temperature done
clear
View Solution play_arrow
question_answer 66)
Consider the following statements:
1. Volumetric efficiency of diesel engines is higher than that of SI engines 2. When a SI engine is throttled; its mechanical efficiency decreases. 3. Specific fuel consumption increases as the power capacity of the engine increases. 4. Inspite of higher compression ratios, the exhaust temperature in diesel engines is much lower than that in SI engines.
Of these statements:
A)
1, 2, 3 and 4 are correct done
clear
B)
1, 2 and 3 are correct done
clear
C)
3 and 4 are correct done
clear
D)
1, 2 and 4 are correct done
clear
View Solution play_arrow
question_answer 67)
Consider the following statements about a rocket engine:
1. It is a very simple in construction and operation. 2. It can attain very high vehicle velocity. 3. It can operate for very long duration.
Of these statements:
A)
1 and 3 are correct done
clear
B)
1 and 2 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1, 2 and 3 are correct done
clear
View Solution play_arrow
question_answer 68)
In summer air-conditioning, the conditioned air passing through the space undergoes a process of:
A)
Sensible cooling done
clear
B)
Sensible heating done
clear
C)
Cooling and dehumidification done
clear
D)
Heating and humidification done
clear
View Solution play_arrow
question_answer 69)
Which of the following are the assumptions involved in the auto-ignition theory put forth for the onset of knock in SI engines?
1. Flame velocity is normal before the onset of auto ignition. 2. A number of end-gas elements auto ignite simultaneously. 3. Preflame reactions are responsible for preparing the end-gas to ignite. Select the correct answer using the codes given below:
A)
1 and 2 done
clear
B)
1 and 3 done
clear
C)
2 and 3 done
clear
D)
1, 2 and 3 done
clear
View Solution play_arrow
question_answer 70)
Suppose, the mean body surface temperature of a certain unclothed person is \[30{}^\circ C,\] the mean temperature of surrounding surfaces is \[21{}^\circ C\] and the air within the room is at \[32{}^\circ C,\] 90 per cent RH, then the person will lose maximum body heat by:
A)
Convection done
clear
B)
Radiation done
clear
C)
Mass transfer done
clear
D)
Convection, radiation mass transfer done
clear
View Solution play_arrow
question_answer 71)
In some carburettors, meter rod and economizer device is used for:
A)
Cold starting done
clear
B)
idling done
clear
C)
Power enrichment done
clear
D)
acceleration done
clear
View Solution play_arrow
question_answer 72)
Which of the following pairs of engine and performance/characteristic is/are correctly matched?
1. Turbojet: Efficiency increases with flight speed 2. SI engine: Lowest specific fuel consumption 3. Turboprop: Suitable for low flight speeds Select the correct answer using the codes given below:
Codes:
A)
1 and 2 done
clear
B)
2 and 3 done
clear
C)
1 and 3 done
clear
D)
2 alone done
clear
View Solution play_arrow
question_answer 73)
Which one of the following is the correct sequence of the position of the given components in a turboprop?
A)
Propeller, Compressor, Turbine, Burner done
clear
B)
Compressor, Propeller, Burner, Turbine done
clear
C)
Propeller, Compressor, Burner, Turbine done
clear
D)
Compressor, propeller. Turbine, Burner done
clear
View Solution play_arrow
question_answer 74)
Consider the following statements: The thrust of rocket engine depends upon:
1. Effective jet velocity 2. Weight of the rocket 3. Rate of propellant consumption
Of these statements:
A)
1 and 2 are correct done
clear
B)
1 and 3 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1, 2 and 3 are correct done
clear
View Solution play_arrow
question_answer 75)
Consider the following statements: In a turbojet engine, thrust may be increased by:
1. Increasing the jet velocity 2. Increasing the mass flow rate of air. 3. After burning of the fuel.
Of these statements:
A)
1 and 2 are correct done
clear
B)
2 and 3 are correct done
clear
C)
1 and 3 are correct done
clear
D)
1, 2 and 3 are correct done
clear
View Solution play_arrow
question_answer 76)
The effective jet exit velocity from a rocket is 2700 m/s. The forward flight velocity is 1350 m/s. the propulsive efficiency of the unit is:
A)
200% done
clear
B)
100% done
clear
C)
66.666% done
clear
D)
33.333% done
clear
View Solution play_arrow
question_answer 77)
Consider the following emission of an IC engine:
(1) CO (2) HC (3) \[N{{O}_{X}}\] (4) Particulates
Which of these emissions cause photochemical smog?
A)
1 and 4 done
clear
B)
1 and 2 done
clear
C)
2 and 3 done
clear
D)
3 and 4 done
clear
View Solution play_arrow
question_answer 78)
Velocity of flame propagation in the SI engine is maximum for a fuel-air mixture which is:
A)
10% richer than stocihiometric done
clear
B)
Equal to stoichiometric done
clear
C)
More than 10% richer than stocihiometric done
clear
D)
10% leaner than stoichiometric done
clear
View Solution play_arrow
question_answer 79)
Divided chamber diesel engines use lower injection pressures compared to open chamber engines because:
A)
Pintle nozzles cannot withstand high injection pressures done
clear
B)
High air swirl does not require high injection pressures for atomization done
clear
C)
High injection pressures may cause over penetration done
clear
D)
High injection pressure causes leakage of the fuel at the pintle done
clear
View Solution play_arrow
question_answer 80)
In a variable speed S.I. Engine, the maximum torque occurs at the maximum:
A)
Speed done
clear
B)
Brake power done
clear
C)
Indicated power done
clear
D)
Volumetric efficiency done
clear
View Solution play_arrow
question_answer 81)
In a domestic refrigerator, a capillary tube controls the flow of refrigerant form the:
A)
Expansion valve to the evaporator done
clear
B)
Evaporator to the thermostat done
clear
C)
Condenser to the expansion valve done
clear
D)
Condenser to the evaporator done
clear
View Solution play_arrow
question_answer 82)
The coefficient of performance (COP) of a refrigerator working as a heat pump is given by:
A)
\[{{(COP)}_{heat\,\,pump}}={{(COP)}_{refrigerator}}+2\] done
clear
B)
\[{{(COP)}_{heat\,\,pump}}={{(COP)}_{refrigerator}}+1\] done
clear
C)
\[{{(COP)}_{heat\,\,pump}}={{(COP)}_{refrigerator}}-1\] done
clear
D)
\[{{(COP)}_{heat\,\,pump}}={{(COP)}_{refrigerator}}\] done
clear
View Solution play_arrow
question_answer 83)
Consider the following steps:
(1) Starting of compressor. (2) Starting of cooling tower pump (3) Starting of chiller water pump (4) Starting of blower motor of cooling coil
The correct sequence of these steps in the starting of a central air conditioning plant using chilled water cooling coil is:
A)
3, 1, 4, 2 done
clear
B)
1, 3, 2, 4 done
clear
C)
3, 2, 1, 4 done
clear
D)
1, 3, 4, 2 done
clear
View Solution play_arrow
question_answer 84)
March List-I with List-II and select the correct answer using the codes given below the Lists:
List-I List-II A. Freon 12 1. Centrifugal systems B. Freon 22 2. Low temperature cold storage C. Freon 11 3. Window type units D. Ammonia 4. Ice plants
Codes:
A)
A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4 done
clear
B)
A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4 done
clear
C)
A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 done
clear
D)
A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2 done
clear
View Solution play_arrow
question_answer 85)
The equivalent diameter D of a circular duct corresponding to a rectangular duct having longer side ?a? and shorter side 'b' the same velocity and Pressure drop is given by:
A)
\[D=\frac{a+b}{ab}\] done
clear
B)
\[D=\frac{ab}{a+b}\] done
clear
C)
\[D=\frac{\left( a+b \right)}{2ab}\] done
clear
D)
\[D=\frac{2ab}{a+b}\] done
clear
View Solution play_arrow
question_answer 86)
Consider the following statements: During sensible heating
1. Moisture content increases 2. Dry bulb temperature and wet bulb temperature increase. 3. Dew point remains constant. 4. Relative humidity increases.
Of these statements
A)
1, 2 and 3 are correct done
clear
B)
2, 3 and 4 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1 and 2 are correct done
clear
View Solution play_arrow
question_answer 87)
Which of the following statements are correct?
1. The human body can lose heat even if temperature. Is less than the atmospheric temperature. 2. Relative humidity can be increased by cooling dehumidification. 3. Warm air increases the rate of radiation of heat from the human body. 4. Increase in air movement increases the evaporation from the human body.
Select the correct answer using the codes given below:
A)
1 and 4 done
clear
B)
2 and 4 done
clear
C)
1 and 3 done
clear
D)
2 and 3 done
clear
View Solution play_arrow
question_answer 88)
When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be:
A)
Cooled and humidified done
clear
B)
Cooled and dehumidified done
clear
C)
Heated and humidified done
clear
D)
Heated and dehumidified done
clear
View Solution play_arrow
question_answer 89)
The atmosphere air at dry bulb temperature of \[15{}^\circ C\] enters a heating coil maintained at \[40{}^\circ C.\] The air leaves the heating coil at \[25{}^\circ C.\] The bypass factor of the heating coil is:
A)
0.376 done
clear
B)
0.476 done
clear
C)
0.6 done
clear
D)
0.67 done
clear
View Solution play_arrow
question_answer 90)
If the specific heats of dry air and water vapour are \[1.00\,\,\text{kJ/kg}-K\] and \[1.88\,\,\text{kJ/kg}-K\] respectively and the humidity ratio is 0.011, then the specific heat of moist air at \[25{}^\circ C.\] and 50% relative humidity will be
A)
\[1.0207\,\,\text{kJ/kg}-K\] done
clear
B)
\[1.869\,\,\text{kJ/kg}-K\] done
clear
C)
\[1.891\,\,\text{kJ/kg}-K\] done
clear
D)
\[0.9793\,\,\text{kJ/kg}-K\] done
clear
View Solution play_arrow
question_answer 91)
Consider the following factors:
(1) Wind velocity (2) Type of a activity (3) Indoor design conditions (4) Door openings
Occupancy load in cooling load calculation depends upon:
A)
1 and 2 done
clear
B)
1 and 3 done
clear
C)
1 and 4 done
clear
D)
2 and 3 done
clear
View Solution play_arrow
question_answer 92)
Match List-I (Basic components of Aqua ammonia refrigeration system) with List-II functions of the components in the system and select the correct answer using the codes given below the lists:
List-I List-II A. Generator 1. Dehydration B. Analyser 2. Removal of vapour from strong aqua - ammonia solution C. Rectifier 3. Producing dry ammonia vapour by removing traces for water particles completely D. Receiver 4. Storage of high pressure liquid ammonia 5. Formation of liquid ammonia from high pressure vapours.
Codes:
A)
A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]5 done
clear
B)
A\[\to \]5, B\[\to \]3, C\[\to \]4, D\[\to \]2 done
clear
C)
A\[\to \]1, B\[\to \]3, C\[\to \]2, D\[\to \]5 done
clear
D)
A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 done
clear
View Solution play_arrow
question_answer 93)
A condenser of refrigeration system rejects heat at rate of 120 kW. While its compressor consumes a power of 30 kW. The coefficient of performance of the system would be:
A)
1/4 done
clear
B)
1/3 done
clear
C)
3 done
clear
D)
4 done
clear
View Solution play_arrow
question_answer 94)
Waste heat can be effectively used in which one of the following refrigeration system?
A)
Vapour compression cycle done
clear
B)
Vapour absorption cycle done
clear
C)
Air refrigeration cycle done
clear
D)
Vortex refrigeration system done
clear
View Solution play_arrow
question_answer 95)
In aircraft, air-refrigeration cycle is used because of:
A)
Low unit weight per tonne of refrigeration done
clear
B)
High heat transfer rate done
clear
C)
Lower temperature at high-altitudes done
clear
D)
Higher coefficient of performance done
clear
View Solution play_arrow
question_answer 96)
A pressure gauge on discharge side of a refrigerant compressor reads too high. The reason could be:
1. Lack cooling water 2. Water temperature being high 3. Dirty condenser surface 4. Refrigerant temperature being too high
Of these reasons:
A)
1, 2 and 4 are valid done
clear
B)
1, 2 and 3 are valid done
clear
C)
2, 3 and 4 are valid done
clear
D)
1, 2 and 4 are valid. done
clear
View Solution play_arrow
question_answer 97)
Consider the following statements:
A decrease in evaporator temperature of a vapour compression machine lead to: 1. An increase in refrigerating effect 2. An increase in specific volume of vapour 3. A decrease in volumetric efficiency of compressor 4. An increase in compressor work.
Of these statements:
A)
1, 3 and 4 are correct done
clear
B)
1, 2 and 3 are correct done
clear
C)
2, 3 and 4 are correct done
clear
D)
2 and 4 are correct. done
clear
View Solution play_arrow
question_answer 98)
Match List-I with Li.st-II and select the correct answer using the codes given below the lists:
List-I List-II A. Air 1. Direct contact freezing of food B. Ammonia 2. Centrifugil compressor system C. Carbon dioxide 3. Large industrial temperature installation D. Refrigerant-11 4. Automotive air conditioners. 5. Aircraft refrigeration
Codes:
A)
A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 done
clear
B)
A\[\to \]5, B\[\to \]3, C\[\to \]1, D\[\to \]2 done
clear
C)
A\[\to \]2, B\[\to \]4, C\[\to \]3, D\[\to \]5 done
clear
D)
A\[\to \]5, B\[\to \]3, C\[\to \]2, D\[\to \]1 done
clear
View Solution play_arrow
question_answer 99)
Consider the following statements:
In psychrometry, wet-bulb temperature is a measure enthalpy of moist air, so that in the psychrometric chart: 1. The constant enthalpy lines are also constant bulb temperature lines. 2. The wet-bulb and dry bulb temperature are same at any condition 3. The wet-bulb and dry-bulb temperature are equal at saturation condition.
Of these statements:
A)
1 alone is correct done
clear
B)
1 and 2 are correct done
clear
C)
1 and 3 are correct done
clear
D)
2 and 3 are correct done
clear
View Solution play_arrow
question_answer 100)
At 100% relative humidity, the wet bulb temperature is:
A)
More than dew point temperature done
clear
B)
Same as dew point temperature done
clear
C)
Less than dew point temperature done
clear
D)
Equal to ambient temperature. done
clear
View Solution play_arrow
question_answer 101)
During the adiabatic cooling of moist-air:
A)
DBT remains constant done
clear
B)
Specific humidity remains constant done
clear
C)
Relative humidity remains constant done
clear
D)
WBT remains constant done
clear
View Solution play_arrow
question_answer 102)
When a stream of moist air is passed over a cold and dry cooling coil such that no condensation takes place, then the air stream will get cooled along the line of
A)
Constant wet bulb temperature done
clear
B)
Constant dew point temperature done
clear
C)
Constant relative humidity done
clear
D)
Constant enthalpy done
clear
View Solution play_arrow
question_answer 103)
For large tonnage (more than 200 tons) air- conditioning applications, which one of the following types of compressors is recommended?
A)
Reciprocating done
clear
B)
Rotating done
clear
C)
Centrifugal done
clear
D)
Screw done
clear
View Solution play_arrow
question_answer 104)
In a cooling tower, "approach" is the temperature difference between the:
A)
Hot inlet water and cold outlet water done
clear
B)
Hot inlet water and WBT done
clear
C)
Cold outlet water and WBT done
clear
D)
DBT and WBT. done
clear
View Solution play_arrow
question_answer 105)
When the discharge pressure is too high in refrigeration system, high pressure control is installed to:
A)
Stop the cooling fan. done
clear
B)
Stop the water circulating pump done
clear
C)
Regulate the flow of cooling water done
clear
D)
Stop the compressor. done
clear
View Solution play_arrow
question_answer 106)
Consider the following statements:
In the case of a vapour compression machine, if the condensing temperature of the refrigerant is closer to the critical temperature, then there will be: (1) Excessive power consumption (2) High compression (3) Large volume flow
Of these statements:
A)
1, 2 and 3 are correct done
clear
B)
1 and 2 are correct done
clear
C)
2 and 3 are correct done
clear
D)
1 and 3 are correct done
clear
View Solution play_arrow
question_answer 107)
Hydrogen is essential in an Electrolux refrigeration system, because:
A)
It acts as a catalyst in the evaporator done
clear
B)
The reaction between hydrogen and ammonia is endothermic in evaporator and exothermic in absorber done
clear
C)
The cooled hydrogen leaving the heat exchanger cools the refrigerant entering the evaporator done
clear
D)
It helps in maintaining a low partial pressure for the evaporating ammonia done
clear
View Solution play_arrow
question_answer 108)
In an ideal refrigeration (reversed Carnot) cycle, the condenser and evaporator temperatures are \[27{}^\circ C\] and \[-\,13{}^\circ C\] respectively. The COP of this cycle would be?
A)
6.5 done
clear
B)
7.5 done
clear
C)
10.5 done
clear
D)
15.0 done
clear
View Solution play_arrow
question_answer 109)
Single-stage vapour compression refrigeration system cannot be used to produce ultralow temperatures because:
A)
Refrigerants for ultra-low temperatures are not available done
clear
B)
Lunbricants for ultra-low temperatures are not available done
clear
C)
Volumetric efficiency will decrease consider-ably done
clear
D)
Heat leakage into the system will be excessive done
clear
View Solution play_arrow
question_answer 110)
Vapour absorption refrigeration system works using the:
A)
Ability of a substances to get easily condensed or evaporated done
clear
B)
Ability of a vapour to get compressed or expanded done
clear
C)
Affinity of a substance for another substance done
clear
D)
Absorptivity of a substance. done
clear
View Solution play_arrow
question_answer 111)
Two summer air-conditioning systems with non-zero by pass factor are proposed for a room with a known sensible and latent heat load. System A operates with ventilation but system B operates without ventilation. Then the:
A)
Bypass factor of system A must be less than the bypass factor of system B done
clear
B)
Bypass factor of system A must be more than the bypass factor of system B done
clear
C)
Apparatus dew point for system A must be lower than the apparatus dew point for system B. done
clear
D)
Apparatus dew point for system A must be higher than the apparatus dew point for system B. done
clear
View Solution play_arrow
question_answer 112)
Evaporative air-cooler used effectively when:
A)
dry-bulb temperature is very close to the wet bulb temperature done
clear
B)
dry-bulb temperature is high and relative humidity is high done
clear
C)
dry-bulb temperature is low and relative humidity is high done
clear
D)
dry-bulb temperature is high and the relative humidity is low. done
clear
View Solution play_arrow
question_answer 113)
The minimum temperature to which water can be cooled in a cooling tower is:
A)
The dew point temperature of air done
clear
B)
The wet-bulb temperature of air done
clear
C)
The dry bulb temperature of air done
clear
D)
The ambient air temperature done
clear
View Solution play_arrow
question_answer 114)
In a vapour compression refrigeration system, throttle valve is used in place of an expander because:
A)
It considerably reduces the system weight. done
clear
B)
It improves the COP, as the condenser is small. done
clear
C)
The positive work in isentropic expansion of liquid is very small. done
clear
D)
It leads to significant cost reduction. done
clear
View Solution play_arrow
question_answer 115)
2000 cc. of air takes \[1{\scriptstyle{}^{1}/{}_{2}}\] minutes to pass through a standard Specimen of sand (5.08 cm high and 5.08 cm in dia.). The manometer indicates pressure as \[5\,\,\text{g/c}{{\text{m}}^{\text{2}}}\text{.}\] In this case the permeability number is:
A)
30 done
clear
B)
42 done
clear
C)
51 done
clear
D)
67 done
clear
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question_answer 116)
A spherical drop of molten metal of radius 2 mm was found to solidify in 10 seconds. A similar drop of radius 4 mm would solidify in:
A)
14.14 second done
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B)
20 seconds done
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C)
18.30 second done
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D)
40 seconds done
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question_answer 117)
The voltage-current characteristics of a DC generator for arc welding is a straight line between an open-circuit voltage of 80 V and short-circuit current of 300A. The generator settings for maximum arc power will be:
A)
80 V and 150 A done
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B)
40 V and 300 A done
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C)
40 V and 150 V done
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D)
V and 300 A done
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question_answer 118)
Consider the following statements:
1. Practically all common refrigerants have approximately the same COP and power requirement. 2. Ammonia mixes freely with lubricating oil and this helps lubrication of compressors. 3. Dielectric strength of refrigerants is an important property in hermetically sealed compressor units. 4. Leakage of ammonia can detected by halide torch method.
Of these statements
A)
1, 2, and 4 are correct done
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B)
2 and 4 are correct done
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C)
1, 3 and 4 are correct done
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D)
1 and 3 are correct done
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question_answer 119)
The most commonly used method for the design of duct size is the:
A)
Velocity reduction method done
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B)
Equal friction method done
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C)
Static regain method. done
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D)
Dual or double dust method. done
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question_answer 120)
The refrigerant used for absorption refrigerators working heat from solar collectors is mixture of water and :
A)
Carbon dioxide done
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B)
Sulphur dioxide done
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C)
Lithium bromide done
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D)
Freon 12 done
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