Refrigeration and AC

JKSSB Junior Engineer (Mechanical) · Technical Subjects (Mechanical) · 11 practice questions with answers and explanations: 6 Easy, 5 Medium, 0 Hard.

Sample questions

Sample Easy question 1

The expansion valve in a refrigeration system:

  1. Cools the condenser
  2. Collects the liquid
  3. Reduces the refrigerant pressure and temperature
  4. Raises the pressure
Show answer

Answer: C. Throttling produces a cold, low-pressure mixture.

Sample Easy question 2

R-134a is a:

  1. Lubricating oil
  2. Fuel
  3. Coolant for boilers
  4. Refrigerant (HFC)
Show answer

Answer: D. It replaced CFC refrigerants such as R-12 because it does not deplete the ozone layer.

Sample Easy question 3

Relative humidity is the ratio of:

  1. Mass of water to mass of dry air
  2. Dry-bulb to wet-bulb temperature
  3. Vapour pressure to total pressure
  4. Actual vapour pressure to saturation vapour pressure at the same temperature
Show answer

Answer: D. It is expressed as a percentage.

Sample Medium question 4

Sensible cooling of air means a process in which:

  1. Dew point rises
  2. Dry-bulb temperature falls and the humidity ratio stays constant
  3. Humidity ratio falls
  4. Wet-bulb temperature rises
Show answer

Answer: B. Only the temperature changes.

Sample Medium question 5

Which refrigerant is used in a vapour absorption refrigerator working on the ammonia–water system?

  1. Air
  2. Carbon dioxide
  3. Ammonia
  4. Water
Show answer

Answer: C. Ammonia is the refrigerant and water is the absorbent.

Sample Medium question 6

In a vapour absorption system, the compressor is replaced by:

  1. A throttle valve
  2. An absorber, a generator and a pump
  3. A cooling tower
  4. A turbine
Show answer

Answer: B. It runs mainly on heat rather than shaft work.

More Technical Subjects (Mechanical) topics for JKSSB Junior Engineer (Mechanical)

Related articles