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Mechanical Engineering Mcqs

The overall isothermal eiffciency of compressor is defined as the ratio of_______________?

  • (A)  isothermal h.p. to the BHP of motor
  • (B)  isothermal h.p. to adiabatic h.p.
  • (C)  power to drive compressor to isothermal h.p.
  • (D)  work to compress air isothermally to work for actual compression
  • (E)  isothermal work to ideal work
Submitted By :Ali Uppal


The pressure and temperature conditions of air at the suction of compressor are_________________?

  • (A)  atmospheric
  • (B)  slightly more than atmospheric
  • (C)  slightly less than atmospheric
  • (D)  pressure slightly more than atmospheric and temperature slightly less than atmospheric
  • (E)  pressure sightly less than atmospheric and temperature slightly more than atmospheric
Submitted By :Ali Uppal


Isothermal compression effeicency can be attained by running the compressor__________________?

  • (A)  at very high speed
  • (B)  at very slow speed
  • (C)  at average speed
  • (D)  at zero speed
  • (E)  isothermally
Submitted By :Ali Uppal


The- most efficient method of compressing air is to compress it_________________?

  • (A)  isothermally
  • (B)  adiabatically
  • (C)  isentropically
  • (D)  isochronically
  • (E)  as per law pV
Submitted By :Ali Uppal


Adiabatic compression is one in which___________________?

  • (A)  temperature during compression remains constant
  • (B)  no heat leaves or enters the compressor cylinder during cornpression
  • (C)  temperature rise follows a linear relationship
  • (D)  work done is maximum
  • (E)  entropy decreases
Submitted By :Ali Uppal


In a forced vortex, the velocity of flow everywhere within the fluid is__________________?

  • (A)  maximum
  • (B)  minimum
  • (C)  zero
  • (D)  non-zero finite
  • (E)  unpredictable
Submitted By :Ali Uppal


For pipes, laminar flow occurs when Roynolds number is__________________?

  • (A)  less than 2000
  • (B)  between 2000 and 4000
  • (C)  more than 4000
  • (D)  less than 4000
  • (E)  none of the above
Submitted By :Ali Uppal


The fluid forces considered in the Navier Stokes equation are__________________?

  • (A)  gravity, pressure and viscous
  • (B)  gravity, pressure and turbulent
  • (C)  pressure, viscous and turbulent
  • (D)  gravity, viscous and turbulent
  • (E)  none of the above
Submitted By :Ali Uppal


All the terms of energy in Bernoulli’s equation have dimension of_______________?

  • (A)  energy
  • (B)  work
  • (C)  mass
  • (D)  length
  • (E)  time
Submitted By :Ali Uppal


An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes________________?

  • (A)  one adiabatic, two isobaric, and one constant volume
  • (B)  two adiabatic and two isobaric
  • (C)  two adiabatic, one isobaric and one constant volume
  • (D)  one adiabatic, one isobaric and two constant volume
  • (E)  two isobaric, two adiabatic and one constant volume
Submitted By :Ali Uppal