Mechanical Engineering Mcqs 1919 MCQs [All-Courses]

Mechanical Engineering MCQs prepared for job test and interview preparation, especially for fresh graduates, students, and candidates appearing in competitive exams. These multiple-choice questions cover key topics such as Machine Design, Theory of Machines, Hydraulic Machines, and other important mechanical engineering concepts.

A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is________________?

A Ammonia

B Carbon dioxide

C Freon

D Brine

Review Detailed Answer

Correct Answer: Carbon dioxide

Where does the lowest temperature occur in a vapour compression cycle ?

A condenser

B evaporator

C compressor

D expansion valve

Review Detailed Answer

Correct Answer: evaporator

Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?

A 1 : 1

B 1 : 9

C 9 : 1

D 1 : 3

Review Detailed Answer

Correct Answer: 1 : 9

Ammonia is __________________?

A non-toxic

B non-inflammable

C toxic and non-inflammable

D highly toxic and inflammable

Review Detailed Answer

Correct Answer: highly toxic and inflammable

Short horizontal lines on pressure-enthalpy chart show__________________?

A constant pressure lines

B constant temperature lines

C constant total heat lines

D constant entropy lines

Review Detailed Answer

Correct Answer: constant pressure lines

One ton of the refrigeration is_________________?

A the standard unit used in refrigeration problems

B the cooling effect produced by melting 1 ton of ice

C the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours

D the refrigeration effect to produce 1 ton of ice at NTP conditions

Review Detailed Answer

Correct Answer: the refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?

A bigger cabinet should be used

B smaller cabinet should be used

C perfectly tight vapour seal should be used

D refrigerant with lower evaporation temperature should be used

Review Detailed Answer

Correct Answer: perfectly tight vapour seal should be used

The advantage of dry compression is that________________?

A it permits higher speeds to be used

B it permits complete evaporation in the evaporator

C it results in high volumetirc and mechanical efficiency

D all of the above

Review Detailed Answer

Correct Answer: all of the above

The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?

A bigger

B smaller

C equal

D smaller/bigger depending on capacity

Review Detailed Answer

Correct Answer: bigger

Under-cooling in a refrigeration cycle_________________?

A increases COP

B decreases COF

C COP remains unaltered

D other factors decide COP

Review Detailed Answer

Correct Answer: increases COP

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Mechanical Engineering Mcqs 1919 MCQs [All-Courses]

All Topics 1919

All Topics 1919

A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is________________?

Where does the lowest temperature occur in a vapour compression cycle ?

Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of___________________?

Ammonia is __________________?

Short horizontal lines on pressure-enthalpy chart show__________________?

One ton of the refrigeration is_________________?

For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then_________________?

The advantage of dry compression is that________________?

The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is_________________?

Under-cooling in a refrigeration cycle_________________?