Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

# Air Compressors MCQs

1. What is the primary mode of operation for a reciprocating compressor?

a) Rotary motion
b) Linear motion
c) Centrifugal motion
d) Oscillating motion

Explanation: Reciprocating compressors operate by using a piston in a cylinder that moves back and forth (linear motion) to compress air.

2. In a single-stage compression process, how does the work input compare to a multi-stage compression process?

a) Work input is higher in single-stage compression
b) Work input is lower in single-stage compression
c) Work input is the same in both single-stage and multi-stage compression
d) Work input depends on the size of the compressor

Answer: a) Work input is higher in single-stage compression
Explanation: Single-stage compression requires higher work input compared to multi-stage compression due to compressing the air to a higher pressure in one stage.

3. Which factor affects the compression process by causing inefficiencies due to the volume of air left in the cylinder after compression?

a) Clearance
b) Temperature
c) Pressure
d) Humidity

Explanation: Clearance is the volume in the cylinder that remains filled with compressed air at the end of the compression stroke. This residual volume reduces the efficiency of compression.

4. What is the indicator diagram used to represent in reciprocating compressors?

a) Electrical power consumption
b) Mechanical efficiency
c) Volumetric efficiency
d) Temperature distribution

Explanation: The indicator diagram in reciprocating compressors represents the volumetric efficiency, which is the ratio of the actual volume of air drawn into the cylinder to the theoretical volume.

5. Which compression process assumes no heat transfer and is reversible?

a) Isentropic
b) Isothermal
d) Polytropic

Explanation: Isentropic compression assumes no heat transfer with the surroundings and is reversible, idealizing the compression process.

6. What type of efficiency measures how well a compressor converts input power into useful work output?

a) Volumetric efficiency
b) Mechanical efficiency
c) Isentropic efficiency
d) Thermal efficiency

Explanation: Mechanical efficiency measures the effectiveness of a compressor in converting input power into useful work output, considering losses due to friction and other factors.

7. In multi-stage compression, what is typically used to reduce the temperature of the air between stages?

a) Supercooling
b) Inter-cooling
c) Pre-cooling
d) Post-cooling

Explanation: Inter-cooling involves cooling the air between stages of compression to reduce its temperature and increase efficiency in multi-stage compression systems.

8. What condition is necessary for achieving the minimum work done during compression?

a) Maximum clearance
b) Minimum clearance
c) Maximum temperature
d) Minimum temperature

Explanation: Minimum clearance reduces the volume of air left in the cylinder after compression, minimizing the work required to compress the air further.

9. Which classification of compressors utilizes a rotating impeller to compress air?

a) Reciprocating compressors
b) Centrifugal compressors
c) Diaphragm compressors
d) Axial compressors