126. One barometric pressure or 1 atmospheric pressure is equal to
(a) 1 kgf/cnr2
(b) 1.033 kgf/cm2
(c) 0 kgf/cm2
(d) 1.0197 kgf/cm2
(e) 100 kgf/cm2
Ans: b
127. The first law of thermodynamics is the law of
(a) conservation of mass
(b) conservation of energy
(c) conservation of momentum
(d) conservation of heat
(e) conservation of temperature
Ans: b
128. A perpetual motion machine is
(a) a thermodynamic machine
(b) a non-thermodynamic machine
(c) a hypothetical machine
(d) a hypothetical machine whose operation would violate the laws of thermodynamics
(e) an inefficient machine
Ans: d
129. Kelvin Planck’s law deals with
(a) conservation of heat
(b) conservation of work
(c) conversion of heat into work
(d) conversion fo work into heat
(e) conservation of mass
Ans: c
130. According to Clausis statement of second law of thermodynamics
(a) heat can’t be transferred from low temperature source to high tempera¬ture source
(b) heat can be transferred for low temperature to high temperature source by using refrigeration cycle.
(c) heat can be transferred from low temperature to high temperature source if COP of process is more than unity
(d) heat can’t be transferred from low temperature to high temperature source without the aid of external energy
(e) all of the above
Ans: d
131. Thermal power plant works on
(a) Carnot cycle
(b) Joule cycle
(d) Rankine cycle
(d) Otto cycle
(e) Brayton cycle
Ans: c
132. Which of the following is an irreversible cycle
(a) carnot
(b) Stirling
(c) ericsson
(d) all of the above
(e) none of the above
Ans: e
133. Otto cycle consists of following four processes
(a) two isothermals and two isentropics
(b) two isentropics and two constant volumes
(c) two isentropics, one constant volume and one constant pressure
(d) two isentropics and two constant pressures
(e) none of the above
Ans: b
134. The efficiency of a Carnot engine depends on
(a) working substance
(b) design of engine
(c) size of engine
(d) type of fuel fired
(e) temperatures of source and sink
Ans: e
135. For same compression ratio and for same heat added
(a) Otto cycle is more efficient than Diesel cycle
(b) Diesel cycle is more efficient than Otto cycle
(c) efficiency depends on other factors
(d) both Otto and Diesel cycles are equal¬ly efficient
(e) none of the above
Ans: a
136. The efficiency of Carnot cycle is maximum for
(a) gas engine
(b) well lubricated engine
(c) petrol engine
(d) steam engine
(e) reversible engine
Ans: e
137. Carnot cycle is
(a) a reversible cycle (ft) an irreversible cycle
(c) a semi-reversible cycle
(d) a quasi static cycle
(e) an adiabatic irreversible cycle
Ans: a
138. Diesel cycle consists of following four processes
(a) two isothermals and two isentropics
(b) two isentropics, and two constant volumes.
(c) two isentropics, one constant volume and one constant pressure
(d) two isentropics and two constant pressures
(e) none of the above
Ans: c
139. If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle
(a) more
(b) less
(c) equal
(d) depends on other factors
(e) none of the above
Ans: c
140. Stirling and Ericsson cycles are
(a) reversible cycles
(b) irreversible cycles
(c) quasi-static cycles
(d) semi-reversible cycles
(e) adiabatic irreversible cycles
Ans: a
141. A cycle consisting of two adiabatic and two constant pressure processes is known as
(a) Otto cycle
(b) Ericsson cycle
(c) Joule cycle
(d) Stirling cycle
(e) Atkinson cycle
Ans: c
142. Reversed joule cycle is called
(a) Carnot cycle
(b) Rankine cycle
(c) Brayton cycle
(d) Bell Coleman cycle
(e) Dual cycle
Ans: c
143. Brayton cycle consists of following four processes
(a) two isothermals and two isentropics
(b) two isentropics and two constant volumes
(c) two isentropics, one constant volume and one constant pressure
(d) two isentropics and two constant pressures
(e) none of the above
Ans: d
144. Which of the following cycles is not a reversible cycle
(a) Carnot
(b) Ericsson
(c) Stirling
(d) Joule
(e) none of the above
Ans: e
145. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
(a) Dual combustion cycle
(b) Diesel cycle
(c) Atkinson cycle
(d) Rankine cycle
(e) Stirling cycle
Ans: c
146. The efficiency of Diesei cycle with decrease in cut off
(a) increases
(b) decreases
(c) remains unaffected
(d) first increases and then decreases
(e) first decreases and then increases
Ans: a
147. Which of the following cycles has maximum efficiency
(a) Rankine
(b) Stirling
(c) Carnot
(d) Brayton
(e) Joule
Ans: c
148. The ideal efficiency of a Brayton cycle without regeneration with increase ni pressure ratio will
(a) increase
(b) decrease
(c) remain unchanged
(d) increase/decrease depending on application
(e) unpredictable
Ans: a
149. The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will
(a) increase
(b) decrease
(c) remain unchanged
(d) increase/decrease depending on application
(e) unpredictable
Ans: b
150. The following cycle is used for air craft refrigeration
(a) Brayton cycle
(b) Joule cycle
(c) Carnot cycle
(d) Bell-Coleman cycle
(e) Reversed-Brayton cycle
Ans: e
151. Gas turbine cycle consists of
(a) two isothermal and two isotropic
(b) two isentropics and two constant volumes
(c) two isentropics, one constant volume and one constant pressure
(d) two isentropics and two constant pressures
(e) none of the above
Ans: d
152. The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that
(a) carnot cycle can’t work with saturated steam
(b) heat is supplied to water at temperature below the maximum temperature of the cycle
(c) a rankine cycle receives heat at two places
(d) rankine cycle is hypothetical
(e) none of the above
Ans: b