41. In order to reduce the rotor speed of an impulse turbine, the method employed is
A. velocity compounding
B. pressure compounding
C. pressure-velocity compounding
D. all of these
42. The nozzle efficiency is the ratio of
A. workdone on the blades to the energy supplied to the blades
B. workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam
C. energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
D. none of the above
43. The friction in the nozzle __________ exit velocity of steam.
A. has no effect on
B. decreases
C. increases
44. In a reaction turbine
A. the steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades
B. the expansion of steam takes place partly in the fixed blades and partly in the moving blades
C. the steam is expanded from a high pressure to a condenser pressure in one or more nozzles
D. the pressure and temperature of steam remains constant
45. A stage, in reaction turbine, is represented by
A. number of casing
B. number of entries of steam
C. number of exits of steam
D. each row of blades
46. When the nozzle operates with the maximum mass flow, the nozzle is said to be
A. choked
B. underdamping
C. overdamping
D. none of these
47. In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
A. velocity increases
B. velocity decreases
C. velocity remains constant
D. pressure remains constant
48. The ratio of the energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam is called mechanical efficiency.
A. Yes
B. No
49. A steam nozzle converts
A. heat energy of steam into kinetic energy
B. kinetic energy into heat energy of steam
C. heat energy of steam into potential energy
D. potential energy into heat energy of steam
50. The maximum discharge of steam through a convergent-divergent nozzle depends upon
A. area of nozzle at throat
B. initial pressure and volume of steam
C. final pressure ofsteam leaving the nozzle
D. both (a) and (b)