Applied Thermodynamics (3161910) MCQs

MCQs of Part-I Reciprocating Compressors

Showing 21 to 30 out of 66 Questions
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21.

In a single acting reciprocating air compressor, without clearance, the compression of air may be

(a)

isothermal
(b)

polytropic
(c)

isentropic
(d)

any one of these
Answer:

Option (d)

22.

Actual compression curve is

(a)

same as isothermal
(b)

same as adiabatic
(c)

better than isothermal and adiabatic
(d)

in between isothermal and adiabatic
Answer:

Option (d)

23.

In a single-stage, single-acting reciprocating air compressor, without clearance volume, the work done is minimum during

(a)

isothermal compression
(b)

isentropic compression
(c)

polytropic compression
(d)

none of these
Answer:

Option (a)

24.

The work done per unit mass of air in compression will be least when 'n' is equal to

(a)

1
(b)

1.2
(c)

1.3
(d)

1.4
Answer:

Option (a)

25.

Adiabatic compression is one in which

(a)

the temperature during compression remains constant
(b)

no heat leaves or enters the compressor cylinder during compression
(c)

temperature rise follows a linear relationship
(d)

work done is maximum
Answer:

Option (b)

26.

Isothermal compression though most efficient, but is not practicable because

(a)

it requires a very big cylinder
(b)

it does not increase pressure much
(c)

it is impossible in practice
(d)

compressor has to run at very slow speed to achieve it
Answer:

Option (d)

27.

Isothermal compression efficiency 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
Answer:

Option (b)

28.

Compression efficiency is compared against

(a)

ideal compression
(b)

adiabatic compression
(c)

isentropic compression
(d)

Isothermal compression
Answer:

Option (d)

29.

In a single stage, single acting reciprocating air compressor without clearance volume, the workdone is maximum during

(a)

isothermal compression
(b)

isentropic compression
(c)

polytropic compression
(d)

none of these
Answer:

Option (b)

30.

The overall isothermal efficiency of the compressor is defined as the ratio of

(a)

work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio
(b)

isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor
(c)

volume of free air delivery per stroke to the swept volume of the piston
(d)

isentropic power to the power required to drive the compressor
Answer:

Option (b)

Showing 21 to 30 out of 66 Questions
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