Power Cycles: A Comprehensive Guide for Engineering Mechanics Students

Question 1

In a Rankine cycle, where is heat primarily added?

Accepted Answer

Boiler

Answer

Condenser

Answer

Turbine

Answer

Pump

Question 2

Which cycle operates with an external combustion process?

Accepted Answer

Rankine cycle

Answer

Otto cycle

Answer

Diesel cycle

Answer

Brayton cycle

Question 3

The efficiency of an Otto cycle is primarily limited by which factors?

Accepted Answer

Compression ratio and specific heat ratio

Answer

Turbine inlet temperature and pressure ratio

Answer

Boiler pressure and condenser temperature

Answer

Valve timing and ignition timing

Question 4

Which assumption is NOT fundamental to the ideal Diesel cycle?

Accepted Answer

Reversible heat addition

Answer

Adiabatic compression and expansion

Answer

Constant specific heats

Answer

Complete combustion

Question 5

What is the primary function of a regenerator in a power cycle?

Accepted Answer

Transfer heat from the hot fluid to the cold fluid

Answer

Increase the pressure of the working fluid

Answer

Reduce the temperature of the combustion gases

Answer

Lubricate the moving parts

Question 6

Compared to the Brayton cycle, what is a notable advantage of the Rankine cycle?

Accepted Answer

Higher thermal efficiency

Answer

Lower emissions

Answer

Simpler design

Answer

Lower operating costs

Question 7

What is the definition of compression ratio in an engine?

Accepted Answer

Ratio of maximum cylinder volume to minimum cylinder volume

Answer

Ratio of minimum cylinder volume to maximum cylinder volume

Answer

Ratio of stroke length to bore diameter

Answer

Ratio of intake valve opening time to exhaust valve opening time

Question 8

What is the main application of the Rankine cycle?

Accepted Answer

Power generation in thermal power plants

Answer

Cooling in refrigeration systems

Answer

Propulsion in jet engines

Question 9

In a Rankine cycle, heat rejection occurs at:

Accepted Answer

Constant pressure

Answer

Constant volume

Answer

Constant temperature

Answer

Constant entropy

Question 10

Which component is NOT found in a Brayton cycle?

Accepted Answer

Condenser

Answer

Compressor

Answer

Turbine

Answer

Intercooler

Question 11

The Otto cycle is a model for which engine?

Accepted Answer

Gasoline engine

Answer

Diesel engine

Answer

Gas turbine engine

Answer

Steam engine

Question 12

Which factor does NOT impact the efficiency of a power cycle?

Accepted Answer

Specific heat of the working fluid

Answer

Heat addition temperature

Answer

Heat rejection temperature

Answer

Cycle type

Question 13

In a regenerative power cycle, the regenerator's function is to:

Accepted Answer

Preheat the working fluid before heat addition

Answer

Cool the working fluid before heat rejection

Answer

Increase the pressure of the working fluid

Answer

Reduce the volume of the working fluid

Question 14

Which type of cycle is used as a topping cycle?

Accepted Answer

Combined cycle

Answer

Cogeneration cycle

Answer

Regenerative cycle

Answer

Reheat cycle

Question 15

Which of the following is NOT a type of thermodynamic power cycle?

Accepted Answer

Refrigeration cycle

Answer

Rankine cycle

Answer

Brayton cycle

Answer

Otto cycle

Question 16

In a Rankine cycle, what is the primary working fluid used?

Accepted Answer

Water

Answer

Air

Answer

Helium

Answer

Carbon dioxide

Question 17

Which component in a Brayton cycle is responsible for adding heat to the working fluid?

Accepted Answer

Combustion chamber

Answer

Compressor

Answer

Turbine

Answer

Heat exchanger

Question 18

What is the main function of a condenser in a thermodynamic power cycle?

Accepted Answer

To remove heat from the working fluid

Answer

To add heat to the working fluid

Answer

To compress the working fluid

Answer

To expand the working fluid

Question 19

Which of the following factors does NOT affect the efficiency of a power cycle?

Accepted Answer

Environmental conditions

Answer

Operating temperature

Answer

Pressure ratio

Answer

Heat input

Question 20

Explain the primary difference between a closed and an open thermodynamic power cycle.

Accepted Answer

Closed cycles use a working fluid that is isolated from the environment, while open cycles do not.

Answer

Open cycles use a working fluid that is isolated from the environment, while closed cycles do not.

Answer

There is no difference between closed and open power cycles.

Answer

Both types of cycles use a working fluid that is isolated from the environment.

Question 21

Which application commonly employs a Brayton cycle?

Accepted Answer

Jet engines

Answer

Power plants

Answer

Refrigerators

Answer

Air conditioners

Question 22

What is the primary advantage of using a combined power cycle?

Accepted Answer

Improved efficiency

Answer

Reduced emissions

Answer

Lower operating costs

Answer

Increased reliability

Question 23

Which component is NOT a part of a Rankine cycle?

Accepted Answer

Evaporator

Answer

Boiler

Answer

Turbine

Answer

Condenser

Question 24

Which cycle type is commonly used in automotive engines?

Accepted Answer

Automotive engines

Answer

Power generation

Answer

Refrigeration

Answer

Air conditioning

Question 25

What equation calculates the work output of a power cycle?

Accepted Answer

Heat added minus heat rejected

Answer

Heat rejected minus heat added

Answer

Heat added plus heat rejected

Answer

Heat added divided by heat rejected

Question 26

Which limitation is associated with the Otto cycle?

Accepted Answer

Narrow operating range

Answer

High thermal efficiency

Answer

Low emissions

Answer

Wide fuel adaptability

Question 27

In a Rankine cycle, what is the primary function of the condenser?

Accepted Answer

Condense steam into water

Answer

Convert water into steam

Answer

Extract heat from steam

Answer

Increase the pressure of steam

Question 28

In a Brayton cycle, the pressure ratio is defined as the ratio of:

Accepted Answer

Maximum pressure to minimum pressure.

Answer

Maximum temperature to minimum temperature.

Answer

Minimum pressure to maximum pressure.

Answer

Minimum temperature to maximum temperature.

Question 29

Which statement about the Otto cycle is accurate?

Accepted Answer

It is a constant-volume heat addition cycle.

Answer

It has a higher thermal efficiency than the Diesel cycle.

Answer

It is commonly used in diesel engines.

Answer

It involves isothermal heat rejection.

Question 30

The Diesel cycle differs from the Otto cycle by:

Accepted Answer

Using constant-pressure heat addition.

Answer

Having a lower compression ratio.

Answer

Using a carburetor for air-fuel mixing.

Answer

Producing less carbon monoxide.

Question 31

The efficiency of a power cycle is calculated as:

Accepted Answer

The ratio of net work output to heat input.

Answer

The ratio of heat input to net work output.

Answer

The ratio of heat rejected to heat added.

Answer

The ratio of heat added to heat rejected.

Question 32

Which factor does NOT affect the efficiency of a power cycle?

Accepted Answer

Age of the equipment

Answer

Pressure ratio

Answer

Temperature ratio

Answer

Type of working fluid

Question 33

A heat exchanger in a power cycle is used to:

Accepted Answer

Transfer heat from one fluid to another.

Answer

Increase the pressure of a fluid.

Answer

Reduce the temperature of a fluid.

Answer

Separate solids from liquids.

Question 34

A condenser in a power cycle is used to:

Accepted Answer

Condense a vapor into a liquid.

Answer

Evaporate a liquid into a vapor.

Answer

Heat a fluid through direct contact.

Answer

Cool a fluid through indirect contact.

Question 35

Which of the following devices is NOT typically used in a power cycle?

Accepted Answer

Motor

Answer

Compressor

Answer

Turbine

Answer

Pump

Question 36

Which component is NOT found in a Rankine power cycle?

Accepted Answer

Compressor

Answer

Turbine

Answer

Condenser

Answer

Heat exchanger

Question 37

What is the primary purpose of a regenerator in a power plant?

Accepted Answer

Preheat air entering the combustor

Answer

Reduce heat loss to the environment

Answer

Increase turbine inlet temperature

Answer

Cool the condenser

Question 38

What solely determines the ideal efficiency of a Carnot cycle?

Accepted Answer

The difference between the heat source and sink temperatures

Answer

The temperature of the heat source

Answer

The temperature of the heat sink

Answer

The pressure ratio

Question 39

Which is a limitation associated with the Otto cycle?

Accepted Answer

Knocking and detonation

Answer

Low thermal efficiency

Answer

Exhaust gas pollution

Answer

High operating pressures

Question 40

In a combined cycle power plant, what is the use of the exhaust heat from the gas turbine?

Accepted Answer

Generate steam for a steam turbine

Answer

Preheat air entering the gas turbine

Answer

Cool the condenser

Answer

Lubricate the bearings

Question 41

What is the purpose of a turbocharger in a Diesel engine?

Accepted Answer

Increase the air mass flow rate into the engine

Answer

Reduce the compression ratio

Answer

Improve fuel efficiency

Answer

Lower exhaust gas emissions

Question 42

Which is a key performance indicator for evaluating power cycles?

Accepted Answer

Thermal efficiency

Answer

Turbine inlet temperature

Answer

Airflow rate

Answer

Fuel consumption

Question 43

Which of the following is NOT a commonly used thermodynamic cycle in engineering applications?

Accepted Answer

Carnot cycle

Answer

Diesel cycle

Answer

Rankine cycle

Answer

Brayton cycle

Question 44

In a Rankine cycle, where does heat rejection occur?

Accepted Answer

Condenser

Answer

Boiler

Answer

Turbine

Question 45

The thermal efficiency of a Brayton cycle is primarily influenced by which two factors?

Accepted Answer

Pressure ratio and specific heat ratio

Answer

Temperature ratio and specific heat ratio

Answer

Specific heat ratio and efficiency ratio

Answer

Pressure ratio and temperature ratio

Question 46

What is a key assumption made in the analysis of an ideal Otto cycle?

Accepted Answer

Constant-volume heat addition and rejection

Answer

Isothermal heat addition and rejection

Answer

Adiabatic heat addition and rejection

Answer

Constant-pressure heat addition and rejection

Question 47

Diesel cycles are primarily used in which type of engine?

Accepted Answer

Internal combustion engines

Answer

Gas turbines

Answer

Refrigerators

Question 48

What is a significant limitation of the Carnot cycle in practical applications?

Accepted Answer

It is not a practical cycle

Answer

It is easy to analyze

Answer

It has a high efficiency

Answer

It can be applied to any working fluid

Question 49

What are the primary factors determining the power output of a gas turbine engine?

Accepted Answer

Mass flow rate and temperature increase across the turbine

Answer

Efficiency and compressor work

Answer

Pressure ratio and specific heat ratio

Question 50

Which of the following power cycles operates on a closed thermodynamic system?

Accepted Answer

Rankine Cycle

Answer

Otto Cycle

Answer

Brayton Cycle

Answer

Diesel Cycle

Question 51

The thermal efficiency of a power cycle is defined as the ratio of:

Accepted Answer

Net work output to heat input

Answer

Heat input to heat rejected

Answer

Heat input to net work output

Answer

Heat rejected to heat input

Question 52

In a Rankine cycle, the process of transferring heat from the working fluid to the surroundings occurs during:

Accepted Answer

Condensation

Answer

Evaporation

Answer

Compression

Answer

Expansion

Question 53

The Brayton cycle, commonly used in gas turbines, is characterized by:

Accepted Answer

Adiabatic compression and expansion

Answer

Constant pressure heat addition and rejection

Answer

Constant volume heat addition and rejection

Answer

Isothermal compression and expansion

Question 54

The Otto cycle, used in gasoline engines, features:

Accepted Answer

Constant volume heat addition and rejection

Answer

Constant pressure heat addition and rejection

Answer

Adiabatic compression and expansion

Question 55

A Diesel cycle differs from an Otto cycle primarily in:

Accepted Answer

Heat addition at constant pressure

Answer

Adiabatic compression and expansion

Answer

Heat addition at constant volume

Answer

Use of a different working fluid

Question 56

The Carnot cycle is a theoretical thermodynamic cycle that is known for its:

Accepted Answer

Maximum possible efficiency for a given temperature difference

Answer

Simplicity of implementation

Answer

High power output

Question 57

A regenerator is a component often included in:

Accepted Answer

Brayton Cycle

Answer

Otto Cycle

Answer

Rankine Cycle

Answer

Diesel Cycle

Question 58

The process of converting mechanical energy into electrical energy in a power plant typically occurs in a:

Accepted Answer

Generator

Answer

Turbine

Answer

Condenser

Answer

Boiler