Question: An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called ____________ furnace?

• 1. Resistance
• 2. Arc
• 3. Low frequency induction
• 4. None of these

Question: Which of the following is a heat treatment furnace ?

• 1. Muffle furnace
• 2. Annealing furnace
• 3. Reheating furnace
• 4. Rotary kiln

Question: In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of__________________?

• 1. Use of non-preheated combustion air
• 2. Use of pulverised solid fuels
• 3. Imperfect mixing of fuel & air and infiltration of air
• 4. Use of excessive positive draft in the furnace

Question: Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above _____________ °C, because corrosion prevails at higher temperatures?

• 1. 350
• 2. 750
• 3. 1050
• 4. 1250

Question: In reverberatory furnace, charge is heated mainly by__________________?

• 1. Conduction
• 2. Natural convection
• 3. Radiation of heat from the roof of the combustion chamber
• 4. None of these

Question: Which one shows the diagrammatic heat balance in a furnace ?

• 1. Sankey diagram
• 2. Cox chart
• 3. Ostwald chart
• 4. None of these

Question: _____________ atmosphere is maintained inside an iron blast furnace?

• 1. Oxidising
• 2. Reducing
• 3. Inert
• 4. Decarburising

Question: If the flame is produced under the hearth and then sweeps up into the heating chamber, this is called a/an ______________ furnace?

• 1. Sidefired
• 2. Underfired
• 3. Covered
• 4. Recirculating

Question: Which of the following is the most important deterrents to an extended use of pulverised coal in boiler firing ?

• 1. Ash disposal problem
• 2. Excessive fly ash discharge from the stack
• 3. Higher power consumption in its transportation
• 4. Erosion of induced draft fan blades

Question: Large tonnage of refractory bricks are dried in a_____________________?

• 1. Shaft furnace
• 2. Rotary hearth furnace
• 3. Tunnel kiln
• 4. Muffle furnace