 # MCQs in Thermodynamics Part IV

(Last Updated On: December 8, 2017) This is the Multiples Choice Questions Part 4 of the Series in Thermodynamics as one of the General Engineering and Applied Sciences (GEAS) topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including past Board Questions in General Engineering and Applied Sciences (GEAS) field.

### Online Questions and Answers in Thermodynamics Series

Following is the list of multiple choice questions in this brand new series:

Thermodynamics MCQs
PART 1: MCQs from Number 1 – 50                        Answer key: PART I
PART 2: MCQs from Number 51 – 100                   Answer key: PART II
PART 3: MCQs from Number 101 – 150                 Answer key: PART III
PART 4: MCQs from Number 151 – 200                 Answer key: PART IV
PART 5: MCQs from Number 201 – 250                 Answer key: PART V
PART 6: MCQs from Number 251 – 300                 Answer key: PART VI
PART 7: MCQs from Number 301 – 350                 Answer key: PART VII
PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII
PART 9: MCQs from Number 401 – 450                 Answer key: PART IX
PART 10: MCQs from Number 451 – 500                Answer key: PART X

### Continue Practice Exam Test Questions Part IV of the Series

Choose the letter of the best answer in each questions.

151. What law states that it is impossible to operate an engine operating in a cycle that will have no other effect than to extract heat from a reservoir and turn it into an equivalent amount of work?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

152. Which statement of the second law of thermodynamics states that no heat engine can have a thermal efficiency of 100 percent?

• A. Kelvin-Planck statement
• B. Clausius statement
• C. Kevin statement
• D. Rankine statement

153. What is the ratio of the useful heat extracted to heating value?

• A. Combustion efficiency
• B. Phase efficiency
• C. Heat efficiency
• D. Work efficiency

154. What is defined as the ratio of the net electrical power output to the rate of fuel energy input?

• A. Combustion efficiency
• B. Thermal efficiency
• C. Overall efficiency
• D. Furnace efficiency

155. What refers to the amount of heat removed from the cooled space in BTS’s for 1 watt-hour of electricity consumed?

• A. Cost efficiency rating
• B. Energy efficiency rating
• C. Coefficient of performance
• D. Cost of performance

156. What law states that it is impossible to build a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

157. What statement of the second law of thermodynamics states that it is impossible to build a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body?

• A. Kelvin-Planck statement
• B. Clausius statement
• C. Kelvin statement
• D. Rankine statement

158. A device that violates either the first law of thermodynamics or the second law of thermodynamics is known as _____.

• A. Ambiguous machine
• B. Universal machine
• C. Perpetual-motion machine
• D. Unique machine

159. A device that violates the first law of thermodynamics is called a _____.

• A. Perpetual-motion machine of the first kind
• B. Universal machine of the first kind
• C. Ambiguous machine of the first kind
• D. Unique machine of the first kind

160. A device that violates the second law of thermodynamics is called a ______.

• A. Perpetual motion machine of the second kind
• B. Universal machine of the second kind
• C. Ambiguous machine of the second kind
• D. Unique machine of the second kind

161. Carnot cycle is the best known reversible cycle which was first proposed in what year?

• A. 1842
• B. 1824
• C. 1832
• D. 1834

162. Who proposed the Carnot cycle?

• A. Sammy Carnot
• B. Sonny Carnot
• D. Suri Carnot

163. The Carnot cycle is composed of how many reversible processes?

• A. 2
• B. 3
• C. 4
• D. 5

164. The Carnot cycle is composed of ______ processes.

• A. One isothermal and one adiabatic
• B. One isothermal and two adiabatic
• C. Two isothermal and one adiabatic
• D. Two isothermal and two adiabatic

165. What is the highest efficiency of heat engine operating between the two thermal energy reservoirs at temperature limits?

• A. Ericson efficiency
• B. Otto efficiency
• C. Carnot efficiency
• D. Stirling efficiency

166. What is a heat engine that operates on the reversible Carnot cycle called?

• A. Carnot heat engine
• B. Ideal heat engine
• C. Most efficient heat engine
• D. Best heat engine

167. What states that thermal efficiencies of all reversible heat engines operating between the same two reservoirs are the same and that no heat engine is more efficient than a reversible one operating between the same two reservoirs?

• A. Ericson principle
• B. Carnot principle
• C. Otto principle
• D. Stirling principle

168. Who discovered the thermodynamic property “Entropy” in 1865?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

169. A process during which entropy remains constant is called ______ process

• A. Isometric
• B. Isochoric
• C. Isobaric
• D. Isentropic

170. “A reversible adiabatic process is necessarily isentropic but an isentropic process is not necessarily reversible adiabatic process.” This statement is:

• A. True
• B. False
• C. May be true and may be false
• D. Absurd

171. The term “isentropic process” used in thermodynamics implies what?

• B. Externally reversible, adiabatic process
• C. Internally reversible, adiabatic process

172. What states that the entropy of a pure crystalline substance at absolute zero temperature is zero?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

173. What law provides an absolute reference point for the determination of entropy?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

174. “The entropy change of a system during a process is equal to the net entropy transfer through the system boundary and the entropy generated within the system”. This statement is known as:

• A. Entropy generation
• B. Entropy change of a system
• C. Entropy balance relation
• D. Third law of thermodynamics

175. What law states that entropy can be created but it cannot be destroyed?

• A. Zeroth law of thermodynamics
• B. First law of thermodynamics
• C. Second law of thermodynamics
• D. Third law of thermodynamics

176. Entropy is transferred by ______.

• A. Work
• B. Heat
• C. Energy
• D. Work and heat

177. During adiabatic, internally reversible process, what is true about the change in entropy?

• A. It is temperature-dependent
• B. It is always greater than zero
• C. It is always zero
• D. It is always less than zero

178. Water boils when:

• A. Its saturated vapor pressure equals to the atmospheric pressure
• B. Its vapor pressure equals 76cm of mercury
• C. Its temperature reaches 212 degree Celsius
• D. Its vapor pressure is 1 gram per sq. cm

179. Which of the following is standard temperature and pressure (STP)?

• A. 0 degree Celsius and one atmosphere
• B. 32 degree Fahrenheit and zero pressure
• C. 0 degree Kelvin and one atmosphere
• D. 0 degree Fahrenheit and zero pressure

180. What is the value of the work done for a closed, reversible isometric system?

• A. Zero
• B. Positive
• C. Negative
• D. Positive or negative

181. “At constant pressure, the volume of a gas is inversely proportional to the pressure”. This is known as ______.

• A. Boyle’s Law
• B. Charles’s Law
• C. Gay-Lussac Law
• D. Ideal gas law

182. Which of the following is the mathematical representation of the Charles’s law?

• A. V1/V2= P2/P1
• B. V1/T1=V2/T2
• C. V1/T2=V2/T1
• D. V1/V2=√P2/√P1

183. Which of the following is the formula for thermal resistance?

• A. Thickness of material/ thermal conductivity of material
• B. 2(thickness of material)/thermal conductivity of material
• C. Thickness of material/ 2(thermal conductivity of material)
• D. Thickness of material x thermal conductivity of material

184. In the process of radiation, energy is carried by electromagnetic waves. What is the speed of electromagnetic waves?

• A. 182,000 miles/second
• B. 184,000 miles/second
• C. 186,000 miles/second
• D. 188,000 miles/second

185. For heat engine operating between two temperatures (T1>T2), what is the maximum efficiency attainable?

• A. Eff = 1 – (T2/T1)
• B. Eff = 1 – (T1/T2)
• C. Eff = T1 – T2
• D. Eff = 1 -  (T2/T1)^2

186. Which one is the correct relation between energy efficiency ratio (EER) and coefficient of performance (COP)?

• A. EER = 2.34 COP
• B. EER = 3.24 COP
• C. EER = 3.42 COP
• D. EER = 4.23 COP

187. The coefficient of performance (COP) is the ratio between the:

• A. Power consumption in watts and heat absorbed per hour
• B. Heat absorbed per hour and the power consumption in watts
• C. Work required and the absorbed heat
• D. Absorbed heat and work required

188. What predicts the approximate molar specific heat at high temperatures from the atomic weight?

• A. Third law of thermodynamics
• B. Law of Dulong and Petit
• C. Mollier diagram
• D. Pressure-enthalpy diagram

189. Considering one mole of any gas, the equation of state of ideal gases is simply the ______ law.

• A. Gay-Lussac law
• B. Dulong and Petit
• D. Henry’s

190. An ideal gas whose specific heats are constant is called _____.

• A. Perfect gas
• B. Natural gas
• C. Artificial gas
• D. Refined gas

191. What are the assumptions of the kinetic gas theory?

• A. Gas molecules do not attract each other
• B. The volume of the gas molecules is negligible compared to the volume of the gas
• C. The molecules behave like hard spheres
• D. All of the above

192. “The total volume of a mixture of non-reacting gases is equal to the sum of the partial volumes.” This statement is known as ______.

• A. Law of Dulong and Petit
• B. Maxwell-Boltzmann law
• C. Amagat’s law

193. An adiabatic process in which there is no change in system enthalpy but for which there is a significant decrease in pressure is called _____.

• A. Isochoric process
• B. Isobaric process
• C. Throttling process
• D. Quasistatic process

194. What is defined as the ratio of the change in temperature to the change in pressure when a real gas is throttled?

• A. Rankine coefficient
• B. Kelvin coefficient
• C. Maxwell-Boltzmann coefficient
• D. Joule-Thomson coefficient

195. The low temperature reservoir of the heat reservoirs is known as ______.

• A. Source reservoir
• B. Heel reservoir
• C. Toe reservoir
• D. Sink reservoir

196. A ______ is a flow in which the gas flow is adiabatic and frictionless and entropy change is zero.

• A. Isentropic flow
• B. Isobaric flow
• D. Uniform flow

197. What refers to the minimum temperature at which combustion can be sustained?

• A. Burn temperature
• B. Kindle temperature
• C. Spark temperature
• D. Ignition temperature

198. What law predicts the dew point of moisture in the fuel gas?

• A. Dalton’s law
• B. Law of Dulong and Petit
• C. Ringelman law
• D. Amagat’s law

199. What law states that one energy from can be converted without loss into another form?

• A. Amagat’s law
• B. Joule’s law
• C. Lussac’s law
• D. Henry’s law

200. Which is NOT a correct statement?

• A. A superheated vapor will not condense when small amount of heat re removed
• B. An ideal gas is a gas that is not a superheated vapor
• C. A saturated liquid can absorb as much heat as it can without vaporizing
• D. Water at 1 atm and room temperature is subcooled

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