Category: Mechanical Engineering

Latest multiple choice questions with answers for mechanical engineering students.

Mechanical Engineering MCQs [Quiz 32]

Q1. Calorific value of coal is of the order of
(a) 200-400 kcal/kg
(b) 800-1200 kcal/kg
(c) 2000-4000 kcal/kg
(d) 5000-8000 kcal/kg
(e) 8000-10,000 kcal/kg.

Q2. Evaporative capacity of boiler is expressed as
(a) kg of steam produced
(b) steam pressure produced
(c) kg of fuel fired
(d) kg of steam produced per kg of fuel fifed
(e) kg of water evaporated.

Q3. Boiler parameters are expressed by
(a) tonnes/hr. of steam
(b) pressure of steam in kg/cm2
(c) temperature of steam in °C
(d) all of the above
(e) none of the above.

Q4. The condition of steam in boiler drum is always
(a) dry
(b) wet
(c) saturated
(d) supersaturated
(e) superheated.

Q5. The balanced draft furnace is one using
(a) induced draft fan and chimney
(b) induced draft fan and forced draft fan
(c) forced draft fan and chimney
(d) any one of the above
(e) none of the above.

Q5. Maximum energy loss in a boiler occurs due to
(a) unburnt carbon in ash
(b) incomplete combustion
(c) ash content
(d) flue gases
(e) radiation losses.

Q6. Overfire burning is the phenomenon of
(a) supply of excess, air
(b) supply of excess coal
(c) burning CO and unburnts in upper zone of furnace by supplying more air
(d) fuel bed firing
(e) none of the above.

Q7. Which is not the correct statement about moisture in coal
(a) inherent moisture and surface mois¬ture are different things
(b) in some coals moisture may be present upto 40%
(c) some moisture in coal helps in better burning which is not possible with completely dry coal
(d) it increases thermal efficiency
(e) moisture in coal is removed before firing by heating it with hot air.

Q8. Deaeration of feed water is carried out because it reduces
(a) cavitation of .boiler feed pumps
(b) corrosion caused by oxygen
(c) heat transfer coefficient
(d) pH value of water
(e) weight of water to be handled

Q9. A supercritical boiler is one that operates above the pressure and temperature of following values
(a) 100 kg/cm2 and 540°C
(b) 1 kg/cm2 and 100°C
(c) 218 kg/cm2 abs and 373°C
(d) 218 kg/cm2 abs and 540°C
(e) 100 kg/cm2 abs and 373°C

Q10. Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
(a) increases
(b) decreases
(c) remains unaffected
(d) first increases and then decreases
(e) first decreases and then increases.

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