Thermal Engineering I Past Paper PDF

# Thermal Engineering - I ## Unit - 1 - Objective question (Roshan Sir.) ### Q2. Renewable energy source is: - Petrol - Forest - Coal - Natural gas **Note:** Sunlight, water, wind, tidal energy, geothermal energy, biomass, forest. ### Q3. Which of the following is considered as a fuel wit...

# Thermal Engineering - I ## Unit - 1 - Objective question (Roshan Sir.) ### Q2. Renewable energy source is: - Petrol - Forest - Coal - Natural gas **Note:** Sunlight, water, wind, tidal energy, geothermal energy, biomass, forest. ### Q3. Which of the following is considered as a fuel with highest calorific value? - Methane - Petrol - LPG - Hydrogen ### Q4. Main component of Biogas is: - Propane - Methane - Butane - Ethane **Note:** Methane & Carbon dioxide. ### Q5. Which is not a renewable resource of energy? - Sun - Water - Petroleum - Wind ### Q6. At which one of the following places was the first atomic station started? - Kalpakkam - Rana pratap sagar - Narora - Tarapur **Note:** Tarapur atomic power station is located in Maharashtra. ### Q7. The most nuclear fuel used in the world is: - Thorium - 232 - Uranium - 235 - Uranium - 238 - Plutonium - 239 ### Q8. How many forms of fossil fuel are there? - One - Two - Three - Four **Note:** Coal, oil, & natural gas. ### Q9. SI unit of energy is: - Watt - Newton - Kilogram - Joule ### Q10. Which among the following is not a renewable source of energy? - Solar energy - Hydro Power - Biomass energy - Geothermal energy ### Q11. Fuel cells are: - Carbon cell - Nuclear cell - Hydrogen cell - Chromium cell ### Q12. Which of the following is a non-renewable resource? - Coal - Geothermal - Solar - Tidal **Note:** Non-renewable coal, oil, nuclear energy, petroleum, natural gas, batteries, etc ### Q13. Which of the following is a conventional way of generating electrical energy? - Tidal energy - Wind power - Thermal power - Solar power **Note:** Renewable source (Non-conventional energy) Ex: wood, solar energy, wind, hydro power, tidal energy, geothermal, biomass energy, etc. **Note:** Non-renewable Source (Conventional energy) Ex: Coal, oil, petroleum, natural gas, nuclear fuel, thermal power etc. ### Q14. Which of the following is a renewable resource? - Solar energy - Coal - Natural gas - Mineral ### Q15. In which of the following conditions bio-gas is produced? - Presence of oxygen - Action of aerobic microorganisms - Action of anaerobic microorganisms - Presence of fertilizers ### Q16. Solar energy is due to: - Chemical reaction - Combustion reaction - Nuclear fission reaction - Nuclear fusion reaction **Note:** Fusion reaction: lighter nuclei (hydrogen) combine to form Helium nuclei. ### Q17. Which of the following is a non-renewable recourse of energy? - Wind power - Hydrogen fuel - Natural gas - Solar energy ### Q18. Heavy water (D2O) in a nuclear reactor serves as a: - Coolant - Moderator - Both A & B ### Q19. Solar cells work on the principle of: - Photovoltaic effect - Photoelectric effect - Photoconductive effect - Photosynthesis ### Q20. Solar energy is-- source of energy - Non-renewable - Exhaustible - Non-conventional - Conventional ### Q21. Which of the following is not a source of renewable energy - Fossil fuel - Hydro electricity - Wind energy - Solar energy ## Unit - 2 ### Q1. In a four stroke engine, the working cycle is completed in: - One revolution of the crank shaft - Two revolutions of the crank shaft - Three revolutions of the crank shaft - Four revolutions of the crank shaft ### Q2. The thermodynamic cycle on which the petrol engine work is: - Otto cycle - Joule cycle - Rankine cycle - Stirling cycle ### Q3. The theoretically correct mixture of air & petrol is: - 10:1 - 15:1 - 20:1 - 25:1 **Note:** Chemically correct stoichiometric ratio is 14.8:1. ### Q4. The compression ratio for a practical diesel engine usually lie in the range: - 5-7 - 10-15 - 7-9 - 16-22 ### Q5. A diesel engine has: - One valve - Three valve - Two valves - Four valves **Note:** Inlet valve, outlet valve, & one for fuel injector value. ### Q6. The thermal efficiency of a two stroke cycle engine is -- a four stroke engine: - Equal to - Greater than - Less than - None of these ### Q7. A two stroke cycle engine gives -- the no. of power strokes as compared to the four stroke engine, at the same speed. - Half - Same - Double - Four time **Note:** - 2-stroke- 2 revolution give one power stroke. - 4-stroke- 4 revolution give only one power stroke. ### Q8. If petrol is used in a diesel engine, then: - Low power will be produced - Efficiency will be low - Higher knocking will occur - Black smoke will be produced ### Q9. A compression ignition engine is a: - Steam engine - Steam turbine - Diesel engine - Petrol engine ### Q10. For same compression ratio & for the same heat added. - Otto cycle is more efficient than Diesel cycle. - Diesel cycle is more efficient than Otto cycle. - Efficiency depends on other factors. - Both Otto & Diesel cycles are equally efficient ###Q11. A petrol engine theoretically operates on: - Constant pressure cycle - Constant volume cycle - Constant temperature cycle - Constant entropy cycle ### Q12. A carburettor is used to supply: - Petrol, air & lubricating oil - Air & diesel - Petrol & lubricating oil - Petrol & air ### Q13. A petrol engine has compression ratio of: - 6 to 10 - 15 to 25 - 10 to 15 - 25 to 40 **Generally 6-12** ### Q14. In diesel engine, the suction contains: - Air only - Fuel only - Mixture of air & fuel - Air or fuel ### Q15. Knocking tendency is an SI engine with increasing: - Compression ratio - Wall temperature - Supercharging - Engine speed **Note:** Decreasing compression ratio knocking tendency decreases. ## Unit - 3 ### Q1. 280-octane (C8H18) has octane number of: - 50 - 70 - 100 ### Q2. Morse test can be conducted for: - Petrol engine - Diesel engine - Multi-cylinder engines - All of these ### Q3. The minimum number of rings in a piston are: - Two - Three - Four - Six ### Q4. Piston compression rings are made of - Cast iron - Aluminium - Bronze - White metal ### Q5. Which is not the material for automobile pistons? - Aluminium alloys - Cast iron - Cast steel - Steel forging ### Q6. The calorific value of petrol is about: - 31500 kJ/kg - 42600 kJ/kg - 34500 kJ/kg - 60700 kJ/kg ### Q7. The ignition coil in a automobile act as a - Rectifier - Switch - Step-up transformer - DC to AC convertor ### Q8. Which is not a part of magneto ignition system? - Battery - Induction coil - Circuit breaker - Condenser ### Q9. For diesel engine, the method of governing employed is: - Quality governing - Quantity governing - Hit & miss governing - None of these **Note:** Governing means the action of varying the fuel supply in accordance with the load demand so that the engine runs at constat speed. ### Q10. Quality of ignition of petrol is measured by: - Octane number - Calorific value - Specific fuel consumption - Cetane number **Note:** - Octane number - for - petrol engine - Cetane number - Diesel engine ### Q11. In diesel engine, the ignition takes place: - Atomicaly due to high temp of compressed fuel - By sparkplug - Automatically due to high temp of air ### Q12. The process of removing the burnt gases from the combustion chamber of the engine cylinder using fresh charge is called - Knocking - Detonation - Supercharging - Scavenging ### Q13. For a four cylinders engine the firing order for evenness of torque is: - 1-2-3-4 - 1-4-3-2 - 1-3-2-4 - 1-3-4-2 **Note:** Best firing order - 4-cylinder - 1-3-4-2 - 6-cylinder - 1-5-3-6-2-4 ### Q14. The self starter for a car is - AC motor - DC series motor - DC shunt motor - DC 12 volt dynamo ### Q15. Most commonly used *Automatica* lubricant in automobile engine is: - Vegetable oil - Animal oil - Mineral oil - Synthetic oil ### Q16. In diesel engines, the duration between the time of injection & ignition is known as: - Pre-ignition period - Delay period - Ignition period - Burning period ## Unit - 4 ### Q1. Morse test is conducted on multi-cylinder engine to find the engine's: - Indicated power - Stroke length - Emission performance - Compression ratio ### Q2. The brake power of the engine is the power available: - At the crankpin - In the engine cylinder - At the crankshaft - None of these ### Q3. The power actually developed by the engine cylinder of an IC engine is known as: - Brake power - Actual power - Indicated power - Frictional power ### Q4. The brake power of an engine is -- the indicated power: - Always equal to - Always greater than - Always less than - None of these **Note:** IP = BP + FOP ### Q5. The thermal efficiency of petrol engine is about: - 15% - 30% - 50% - 70% ### Q6. The morse test is used to find I.O.P of: - Single cylinder petrol engine - Single cylinder diesel engine - Multi-cylinder engine - None of these ### Q7. The ratio of indicated thermal efficiency to the air standard efficiency is called: - Mechanical efficiency - Overall efficiency - Volumetric efficiency - Relative efficiency **Note:** $ηm$ = B.P (mechanical efficiency) ### Q8. Indicated power of a 4-stroke engine is equal to. - PLAN - PLAN/2 - 2PLAN - 4PLAN **Where:** - P = mean effective pressure - L = stroke length - A = Area of piston - N = rpm of engine ### Q9. The thermal efficiency of diesel engine is about: - 15% - 30% - 50% - 70% ### Q10. Carburettor is used in - Petrol engine - Gas engine - Diesel engine - Steam engine ### Q11. Minimum work input is achieved to the compressor if the compression process is: - Adiabatic - Polytropic - Isentropic - Isothermal **Note:** Minimum work done in isothermal process & maximum in Isentropicprocess ### Q12. Optimum intermediate pressure in two stage compression is: - Arithmetic mean of suction & delivery pressure - Geometric mean of suction & delivery pressure - Depend on the inter cooling fluid used - 50% of the difference of P1 & P2 **Note:** *P₂* = ( *P₁P₃* )^1/2 ### Q13. For air compressor, least work input will be needed if the compressor is: - Hyperbolic - Polytropic - Isentropic - Isothermal ### Q14. Mechanical efficiency of reciprocating air compressor is expressed as: - B.O.P/I.O.P - F.O.P/B.P - I.P/B.P - F.O.P/I.O.P ### Q15. Rotary compressor is best suited for: - Small quantity at higher pressure air - Large quantity at higher pressure air - Large quantity at low pressure air - Small quantity at low pressure air ### Q16. Reciprocating air compressor are used: - Low discharge of air at very high pressure - High discharge of air at very high pressure - Low discharge of air at low pressure - High discharge of air at low pressure ### Q17. Work done during isothermal compression in single stage reciprocating air compression is: - W = P₁V₁ In (P₁/P₂) - W = P₁V₁ In (P₂/P₁) - W = hV₁ In (P₁/P₂) - W = MRT₁ In (P₁/P₂) ### Q18. Work done during polytropic compression is: - W = n/n-1 P₁V₁ [ ( P₂/P₁ )^n-1/n - 1] - W = 2/n-1 P₁V₁ [ ( P₂/P₁ )^n-1/n - 1] - W = n/n-1 P₁V₁ [ ( P₁/P₂ )^n-1/n - 1] - W = 2n/n-1 P₁V₁ [ ( P₂/P₁ )^n-1/n - 1] ### Q19. A compressor mostly used for supercharging of IC engine is: - Radial flow compressor - Axial flow compressor - Roots blocuer compressor - Reciprocating compressor ### Q20. The maximum delivery pressure in a rotary air compressor is - 10 bar - 30 bar - 20 bar - 40 bar ### Q21. The multi-stage compression of air as compared to single stage compression: - Improve volumetric efficiency for the given pressure ratio - Give more uniform torque - Reduce work done per kg - All of the above ## Unit - 5 ### Q1. One ton of refrigeration is equal to: - 21 kJ/min - 420 kJ/min - 210 kJ/min - 620 kJ/min **Note:** 1 TR = 210 kJ/min = 3.5 KW ### Q2. The COP of domestic refrigerators: - < 1 - = 1 - > 1 - Depends on the make ### Q3. Psychrometer indicates: - DBT alone - DBT & WBT - DPT - WBT alone ### Q4. The comfort condition normally used in India is: - 24^oC - 60% RH (Relative humidity) - 24^oC - 70% RH -15^oC - 80% RH - 30^oC - 40% RH ### Q5. A Bell Coleman cycle is: - Reversed Stirling cycle - Reversed Carnot cycle - Reversed Joule cycle - Reversed Atkinson cycle ### Q6. Dew point temp is always an indication of: - Dryness of air - Latent heat - Moisture content in air - Coolness of air ### Q7. The expansion process in the throttling device of vapour compression cycle is: - Isothermal process - Adiabatic process - Isentropic process - Isenthalpic process ### Q8. One tonne refrigerating machine means that: - One tonne is the total mass of the machine - One tonne of refrigerant is used - One tonne of water can be converted into ice - One tonne of ice when melts from 0^o C in 24 hours, the refrigeration effect produced is equivalent to 210 kJ/min. **All the best** **Jai mechanical! **