Mechanical Engineering MCQs

1. Which of the following is a scalar quantity? a) Velocity b) Force c) Speed d) Acceleration Answer: c) Speed 2. In a four-stroke engine, how many times does the crankshaft rotate during one complete cycle? a) 1 b) 2 c) 3 d) 4 Answer: b) 2 3. What is the unit of viscosity? a) Pascal b) Newton c) Pascal-second d) Newton-second Answer: c) Pascal-second 4. The first law of thermodynamics is a statement of: a) Conservation of energy b) Conservation of mass c) Conservation of momentum d) Conservation of work Answer: a) Conservation of energy 5. Which material has the highest thermal conductivity? a) Copper b) Aluminum c) Stainless steel d) Glass Answer: a) Copper 6. The efficiency of an ideal Carnot engine depends on: a) The working fluid b) The pressure c) The temperatures of the heat reservoirs d) The volume of the system Answer: c) The temperatures of the heat reservoirs 7. In a Rankine cycle, the working fluid is usually: a) Air b) Water c) Helium d) Nitrogen Answer: b) Water 8. Which of the following processes is used for manufacturing of seamless tubes? a) Rolling b) Extrusion c) Drawing d) Piercing Answer: d) Piercing 9. The unit of strain is: a) Newton b) Pascal c) Joule d) Dimensionless Answer: d) Dimensionless 10. What is the typical value of the modulus of elasticity for steel? a) 210 GPa b) 70 GPa c) 100 GPa d) 50 GPa Answer: a) 210 GPa 11. The phenomenon of “creep” in materials refers to: a) Sudden failure under static load b) Gradual deformation under constant load c) Fracture due to cyclic loading d) Elastic deformation under load Answer: b) Gradual deformation under constant load 12. In a hydrodynamic journal bearing, the pressure is: a) Minimum at the point of maximum velocity b) Maximum at the point of minimum velocity c) Uniform throughout d) Zero at the load point Answer: b) Maximum at the point of minimum velocity 13. A device that converts mechanical energy into electrical energy is called: a) Motor b) Generator c) Transformer d) Rectifier Answer: b) Generator 14. Which of the following is not a thermodynamic property? a) Temperature b) Pressure c) Volume d) Heat Answer: d) Heat 15. The property of a material to resist fracture due to high impact loads is known as: a) Toughness b) Hardness c) Brittleness d) Ductility Answer: a) Toughness 16. The critical temperature above which a gas cannot be liquefied is called: a) Boiling point b) Melting point c) Critical point d) Freezing point Answer: c) Critical point 17. The ratio of the lateral strain to the longitudinal strain in a material under tension is known as: a) Young’s modulus b) Shear modulus c) Bulk modulus d) Poisson’s ratio Answer: d) Poisson’s ratio 18. The specific speed of a pump is defined as the speed of a geometrically similar pump that would deliver: a) Unit discharge at unit head b) Unit discharge at unit power c) Unit power at unit head d) Unit power at unit efficiency Answer: a) Unit discharge at unit head 19. A fastener used to secure objects by inserting through a hole and then deforming the end is called a: a) Bolt b) Rivet c) Nut d) Screw Answer: b) Rivet 20. The function of a governor in an engine is to: a) Control the fuel supply b) Regulate the speed c) Reduce vibrations d) Increase the efficiency Answer: b) Regulate the speed 21. The efficiency of a real heat engine is always: a) Equal to Carnot efficiency b) Less than Carnot efficiency c) More than Carnot efficiency d) Zero Answer: b) Less than Carnot efficiency 22. A cantilever beam is subjected to a load at the free end. The maximum bending moment occurs at the: a) Free end b) Mid-point c) Fixed end d) Load point Answer: c) Fixed end 23. The phenomenon of “water hammer” in pipelines is caused by: a) Steady flow of water b) Sudden closure of valve c) Gradual increase in temperature d) Continuous operation of pump Answer: b) Sudden closure of valve 24. In a CNC machine, the code G01 is used for: a) Rapid positioning b) Linear interpolation c) Circular interpolation d) Dwell Answer: b) Linear interpolation 25. The term “hysteresis” is associated with: a) Elastic deformation b) Plastic deformation c) Magnetic materials d) Fluid flow Answer: c) Magnetic materials 26. In an ideal gas, the internal energy depends on: a) Volume b) Pressure c) Temperature d) Mass Answer: c) Temperature 27. In a four-bar linkage, the condition for Grashof’s law is: a) 𝑆 + 𝐿 < 𝑃 + 𝑄 S+L<P+Q b) 𝑆 + 𝐿 > 𝑃 + 𝑄 S+L>P+Q c) 𝑆 + 𝑃 < 𝐿 + 𝑄 S+P<L+Q d) 𝑆 + 𝐿 = 𝑃 + 𝑄 S+L=P+Q Answer: a) 𝑆 + 𝐿 < 𝑃 + 𝑄 S+L<P+Q 28. The term “Reynolds number” is used to describe: a) Heat transfer b) Fluid flow c) Phase change d) Stress-strain relationship Answer: b) Fluid flow 29. The instrument used to measure small angles is called: a) Vernier caliper b) Micrometer c) Sine bar d) Theodolite Answer: c) Sine bar 30. The thermal efficiency of a Rankine cycle can be increased by: a) Decreasing the condenser pressure b) Increasing the boiler pressure c) Superheating the steam d) All of the above Answer: d) All of the above 31. A centrifugal pump loses its prime during operation due to: a) Low speed b) High speed c) Air entrainment d) High viscosity of the fluid Answer: c) Air entrainment 32. The principle of a hydraulic press is based on: a) Bernoulli’s theorem b) Pascal’s law c) Archimedes’ principle d) Newton’s second law Answer: b) Pascal’s law 33. The phenomenon of “thermal expansion” occurs because of: a) Increase in atomic vibrations b) Decrease in atomic vibrations c) Decrease in temperature d) Increase in pressure Answer: a) Increase in atomic vibrations 34. The ratio of inertial forces to viscous forces is known as: a) Mach number b) Prandtl number c) Reynolds number d) Nusselt number Answer: c) Reynolds number 35. The modulus of rigidity is also known as: a) Young’s modulus b) Bulk modulus c) Shear modulus d) Elastic modulus Answer: c) Shear modulus 36. In an ideal gas cycle, the process in which heat is added at constant pressure is known as: a) Isothermal process b) Isobaric process c) Isochoric process d) Adiabatic process Answer: b) Isobaric process 37. The term “machining” refers to: a) Casting b) Welding c) Material removal d) Forging Answer: c) Material removal 38. The bending stress in a beam is proportional to: a) Shear force b) Bending moment c) Torsional moment d) Axial force Answer: b) Bending moment 39. The “critical speed” of a shaft is the speed at which: a) Torsional vibrations are minimized b) Bending stress is maximized c) Resonance occurs d) Shear stress is zero Answer: c) Resonance occurs 40. In fluid mechanics, the point in the fluid where the velocity is zero is called: a) Stagnation point b) Streamline c) Vortex d) Boundary layer Answer: a) Stagnation point 41. The efficiency of a heat engine is defined as the ratio of: a) Work output to heat input b) Work input to heat output c) Heat output to heat input d) Work output to work input Answer: a) Work output to heat input 42. The process of increasing the diameter of a hole is called: a) Drilling b) Reaming c) Boring d) Tapping Answer: c) Boring 43. The term “entropy” in thermodynamics is a measure of: a) Energy b) Temperature c) Disorder d) Pressure Answer: c) Disorder 44. The process of heat transfer by direct contact of particles is known as: a) Conduction b) Convection c) Radiation d) Emission Answer: a) Conduction 45. A “gear ratio” is the ratio of: a) Input torque to output torque b) Output speed to input speed c) Input speed to output speed d) Input power to output power Answer: c) Input speed to output speed 46. The material used for making the core of a transformer is: a) Copper b) Aluminum c) Silicon steel d) Brass Answer: c) Silicon steel 47. The Coefficient of Performance (COP) of a refrigerator is defined as the ratio of: a) Work input to heat output b) Heat output to work input c) Heat removed to work input d) Work input to heat removed Answer: c) Heat removed to work input 48. The measure of a material’s ability to conduct heat is called: a) Thermal resistance b) Thermal conductivity c) Thermal diffusivity d) Specific heat Answer: b) Thermal conductivity 49. A turbine converts: a) Electrical energy into mechanical energy b) Mechanical energy into electrical energy c) Thermal energy into mechanical energy d) Chemical energy into mechanical energy Answer: c) Thermal energy into mechanical energy 50. The device used to measure the flow rate of a fluid in a pipe is: a) Thermometer b) Manometer c) Flowmeter d) Barometer Answer: c) Flowmeter

Mechanical Engineering MCQs

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