1. Rankine cycle comprises of ___________
a) two isentropic processes and two constant volume processes
b) two isentropic processes and two constant pressure processes
c) two isothermal processes and two constant pressure processes
d) none of the mentioned
Explanation: A rankine cycle is a thermodynamic cycle which comprises of two isentropic and two isobaric processes which is a major thermodynamic cycle in various applications.
2. In Rankine cycle the work output from the turbine is given by ___________
a) change of internal energy between inlet and outlet
b) change of enthalpy between inlet and outlet
c) change of entropy between inlet and outlet
d) change of temperature between inlet and outlet
Explanation: The power output from the turbine is given by the change of internal energy between inlet and outlet.
3. Regenerative heating i.e., bleeding steam to reheat feed water to boiler ___________
a) decreases thermal efficiency of the cycle
b) increases thermal efficiency of the cycle
c) does not affect thermal efficiency of the cycle
d) may increase or decrease thermal efficiency of the cycle depending upon the point of extraction of steam
Explanation: Bleeding decreases the thermal efficiency of the cycle as it reheats feed water to the boiler.
4. In a regenerative feed heating cycle, the greatest economy is affected ___________
a) when steam is extracted from only one suitable point of steam turbine
b) when steam is extracted from several places in different stages of steam turbine
c) when steam is extracted only from the last stage of steam turbine
d) when steam is extracted only from the first stage of steam turbine
Explanation: Steam extraction is an important factor in deciding the economy of a regenerative cycle. The greatest economy is affected when steam is extracted from several places in different stages of steam turbine.
5.What is the relation between efficiencies of Rankine cycle and Carnot cycle for the same pressure ratio?
a) (ηr) = (ηc)
b) (ηr) > (ηc)
c) (ηr) < (ηc)
d) none of the mentioned
Explanation: The relation between efficiencies of Rankine cycle and Carnot cycle for the same pressure ratio is given by,
(ηr) < (ηc ).
6. The maximum efficiency of Rankine cycle (ηr) is the function of ___________
a) the mean temperature of heat addition (Tm) only
b) the mean temperature of heat addition (Tm) and temperature of steam at the exit of the turbine
c) the mean temperature of heat addition (Tm) and temperature of steam at the entry of the turbine
d) the mean temperature of heat addition (Tm) and temperature of steam at exit of the condenser
Explanation: The maximum efficiency of Rankine cycle (ηr) is the function of
the mean temperature of heat addition (Tm) only.
7. What is the effect of superheated steam on efficiency of Rankine cycle?
a) efficiency of Rankine cycle decreases with increase in superheat of the steam
b) efficiency of Rankine cycle increases with increase in superheat of the steam
c) efficiency of Rankine cycle is not affected by change in superheat of the steam
d) none of the mentioned
Explanation: The effect of superheated steam on efficiency of Rankine cycle is that the efficiency of Rankine cycle increases with increase in superheat of the steam.
8. When the pressure at which heat is added in Rankine cycle increases, the moisture content at the turbine exhaust?
a) increases
b) decreases
c) remains same
d) cannot say
Explanation: With an increase in the pressure at which heat is added in Rankine cycle increases, the moisture content at the turbine exhaust increases.
9. What is the condition for increasing the chances of corrosion of blades of turbine?
a) decrease in the pressure difference between which the Rankine cycle operates
b) increase in the pressure difference between which the Rankine cycle operates
c) increases and decreases in the pressure difference between which the Rankine cycle operates
d) none of the mentioned
Explanation: The condition for increasing the chances of corrosion of blades of turbine is an increase in the pressure difference between which the Rankine cycle operates.
10. What is the maximum content of moisture allowed at the turbine exhaust in the steam power plant?
a) 50 %
b) 60 %
c) 30 %
d) 15 %
Explanation: The maximum content of moisture allowed at the turbine exhaust in the steam power plant is 15 %.