61. A particular coal is said to be free burning when it September 7, 2025 by Admin Burns completely Gives smokeless burning Shows little or no fusing action None of these ✅ The correct answer is option C.
62. The difference between total carbon and fixed carbon of coal will be minimum in case of September 7, 2025 by Admin Lignite Bituminous coal Anthracite High temperature coke (V.M < 0.5%) ✅ The correct answer is option D.
63. A coal containing high amount of volatile matter will have September 7, 2025 by Admin Low ignition temperature Very little ash content High fusion point of its ash Low adiabatic flame temperature ✅ The correct answer is option A.
64. Oxygen required for theoretically complete combustion of 1 Nm³ methane is __________ Nm³. September 7, 2025 by Admin 2 4 6 1 ✅ The correct answer is option A.
65. Bunsen burner is an example of a/an __________ burner. September 7, 2025 by Admin Inside mixing/premix type Outside mixing/diffusion flame/nozzle mix type Rotary cup Submerged combustion ✅ The correct answer is option A.
66. Blast furnace coke is made from coal by September 7, 2025 by Admin Low temperature carbonisation High temperature carbonisation Medium temperature carbonisation Heating the coal in an oven in presence of air ✅ The correct answer is option B.
67. Height of coke oven is limited (say maximum upto 7 metres) mainly by the September 7, 2025 by Admin Problem of uniform heating along its height Structural strength of silica bricks Problem in door cleaning Buckling of ram of pusher car at the time of coke pushing ✅ The correct answer is option A.
68. Efficiency of the combustion of a fuel is judged by the __________ the flue gas. September 7, 2025 by Admin %of CO₂ in % of O₂in Temperature of Colour of ✅ The correct answer is option B.
69. Preheating of coal charge for the coke ovens reduces the September 7, 2025 by Admin Time of carbonisation Yield of gas and tar Fuel consumption in coking All of the above ✅ The correct answer is option D.
70. Deficiency of combustion air during combustion of a gaseous fuel September 7, 2025 by Admin Lengthens the flame Causes heat loss of fuel by its partial combustion Both A & B Shortens the flame ✅ The correct answer is option C.