51. The actual vacuum in a condenser is equal to
barometric pressure + actual pressure
barometric pressure – actual pressure
gauge pressure + atmospheric pressure
gauge pressure – atmos
✅ The correct answer is option B.
Steam Boilers and Engines MCQs
52. In a Tandem type compound engine, the high pressure and low pressure cylinders
have common piston rod
are set at 90°
have separate piston rods
are set in V – arrange
✅ The correct answer is option A.
53. When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as
internally fired boiler
externally fired boiler
natural circulation boiler
forced circulation boi
✅ The correct answer is option C.
54. The ratio of heat equivalent to brake power to the energy supplied in steam is known as
mechanical efficiency
overall efficiency
indicated thermal efficiency
brake thermal efficien
✅ The correct answer is option D.
55. The fire tubes in a Cochran boiler usually have __________ diameter.
6.25 mm
62.5 mm
72.5 mm
92.5 mm
✅ The correct answer is option B.
56. A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly
150 kg/h
210 kg/h
280 kg/h
340 kg/h
✅ The correct answer is option D.
57. The relative efficiency is defined as the
ratio of thermal efficiency to Rankine efficiency
ratio of brake power to the indicated power
ratio of heat equivalent to indicated power to the energy supplied in steam
product of thermal eff
✅ The correct answer is option A.
58. When the expansion of steam is carried out in a single cylinder and then exhausted into the atmosphere or a condenser, the engine is said to be a simple steam engine.
Correct
Incorrect
✅ The correct answer is option A.
59. An economiser is generally placed between
last superheater or reheater and air preheater
induced draft fan and forced draft fan
air preheater and chimney
none of the above
✅ The correct answer is option A.
60. In a compound steam engine, the first stage of expansion is carried out in a high pressure cylinder whereas the last expansion is completed in low pressure cylinder. The diameter of high pressure cylinder is __________ the lowpressure cylinder.
equal to
less than
more than
✅ The correct answer is option B.