Mechanical Engineering Mcqs

Pick up the wrong statement ?
  • (A)  centrifugal compressors deliver prac-tically constant pressure over a considerable range of capacities
  • (B)  Axial flow compressors have a sub-stantially constant delivery at variable pressures
  • (C)  centrifugal compressors have a wider stable operating range than axial flow compressors
  • (D)  axial flow compressors are bigger in diameter compared to centrifugal type
  • (E)  axial flow compressors apt to be longer as compared to centrifugal type
Pick up the correct statement ?
  • (A)  gas turbine uses low air-fuel ratio to economise on fuel
  • (B)  gas turhine uses high air-fuel ratio to reduce outgoing temperature
  • (C)  gas turbine uses low air-fuel ratio to develop the high thrust required
  • (D)  all of the above
  • (E)  none of the above
Pick up the wrong statement ?
  • (A)  large gas turbines employ axial flow compressors
  • (B)  axial flow compressors are more stable than centrifugal type compressors but not as efficient
  • (C)  axial flow compressors have high capacity and efficiency
  • (D)  axial flow compressors have instability region of operation
  • (E)  centrifugal compressors are used mainly on low flow pressure ratio gas turbines
Choose the correct statement ________________?
  • (A)  gas turbine requires lot of cooling water
  • (B)  gas turbine is capable of rapid start up and loading
  • (C)  gas turbines have flat efficiency at part loads
  • (D)  gas turbines have high standby losses and require lot of maintenance
  • (E)  gas turbines can be used to generate power only
Pick up the correct statement ?
  • (A)  large gas turbines use radial inflow turbines
  • (B)  gas turbines have their blades similar to steam turbine
  • (C)  gas .turbine’s blade will appear as impulse section at the hub and as a reaction section at tip
  • (D)  gas turbines use both air and liquid cooling
  • (E)  all of the above are correct.
Pick up the wrong statement ?
  • (A)  pulsojet requires no ambient air for propulsion
  • (B)  ramjet-engine has no turbine
  • (C)  turbine drives compressor in a burbojet
  • (D)  bypass turbo-jet engine increases the thrust without adversely affecting, the propulsive efficiency and fuel economy
  • (E)  propeller is an indirect reaction device
Pick up the correct statement?
  • (A)  closed cycle gas turbine is an I.C engine
  • (B)  gas turbine uses same working fluid over and over again
  • (C)  air-fuel ratio in a gas turbine is 100 : 1
  • (D)  ideal efficiency of closed cycle gas turbine plant is more than carnot cycle efficiency
  • (E)  thrust in turbo-jet is produced by nozzle exit gases
Pick up the false statement ?
  • (A)  gas turbine is a self-starting unit
  • (B)  gas turbine does not require huge quantity of water like steam plant
  • (C)  exhaust losses in gas turbine are high due to large mass flow rate
  • (D)  overall efficiency of gas turbine plant is lower than that of a reciprocating engine
  • (E)  gas turbine can be easily started and stopped and thus is best suited for peaking demands