ক) when the cross-section of the nozzle increases continuously from entrance to exit
খ) when the cross-section of the nozzle decreases continuously from entrance to exit
গ) when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
ঘ) none of the above
০২। A nozzle is said to be a convergent-divergent nozzle, when the cross-section of a nozzle first decreases from its entrance to throat and then increases from its throat to exit.
ক) True
খ) False
০৩। A nozzle is said to be a divergent nozzle
ক) when the cross-section of the nozzle increases continuously from entrance to exit
খ) when the cross-section of the nozzle decreases continuously from entrance to exit
গ) when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
ঘ) none of the above
০৪। A regenerative steam cycle renders
ক) increased work output per unit mass of steam
খ) decreased work output per unit mass of steam
গ) increased thermal efficiency
ঘ) decreased work output per unit mass of steam as well as increased thermal efficiency
০৫। A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
ক) 79 m/s
খ) 188 m/s
গ) 450 m/s
ঘ) 900 m/s
০৬। A single stage turbine is not used because it requires large reduction gearing due to very high rotational speed.
ক) Agree
খ) Disagree
০৭। A stage, in reaction turbine, is represented by
ক) number of casing
খ) number of entries of steam
গ) number of exits of steam
ঘ) each row of blades
০৮। A steam nozzle converts
ক) heat energy of steam into kinetic energy
খ) kinetic energy into heat energy of steam
গ) heat energy of steam into potential energy
ঘ) potential energy into heat energy of steam
০৯। A steam turbine, in which a part of the steam after partial expansion, is used for process heating and the remaining steam is further expanded for power generation, is known as
ক) back pressure turbine
খ) pass out turbine
গ) low pressure turbine
ঘ) impulse turbine
১০। A turbine is said to have an axial discharge when the steam leaves the blade tip at __________ to the direction of the blade motion.
ক) 60°
খ) 90°
গ) 180°
ঘ) 270°
১১। An impulse turbine as compared to a reaction turbine, for a given power has __________ row of blades.
ক) equal
খ) less
গ) more
১২। Blading efficiency is also known as
ক) stage efficiency
খ) diagram efficiency
গ) nozzle efficiency
ঘ) none of these
১৩। Curtis turbine is a
ক) simple reaction turbine
খ) velocity compounded turbine
গ) pressure compounded turbine
ঘ) pressure-velocity compounded turbine
১৪। De-Laval turbine is a
ক) simple impulse turbine
খ) simple reaction turbine
গ) impulse-reaction turbine
ঘ) none of these
১৫। De-Laval turbine is a
ক) single rotor impulse turbine
খ) multi-rotor impulse turbine
গ) impulse reaction turbine
ঘ) none of these
১৬। De-Laval turbines are mostly used
ক) where low speeds are required
খ) for small power purposes and low speeds
গ) for large power purposes
ঘ) for small power purposes and high speeds
১৭। Degree of reaction is defined as the ratio of
ক) heat drop in fixed blades to the heat drop in moving blades
খ) heat drop in moving blades to the heat drop in fixed blades
গ) heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades
ঘ) heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades
১৮। During flow through a nozzle, no heat is supplied or rejected by the steam.
ক) Agree
খ) Disagree
১৯। For a Parson‘s reaction turbine, if α1 and α2 are fixed blade angles at inlet and exit respectively and β1 and β2 are the moving blade angles at entrance and exit respectively, then