Question: Induction furnaces are employed for which of the following ?

• 1. Heat treatment of castings
• 2. Heating of insulators
• 3. Melting aluminium
• 4. None of the above

Question: Which of the following will happen if the thickness of refractory wall of furnace is increased ?

• 1. Heat loss through furnace wall will increase
• 2. Temperature inside the furnace will fall
• 3. Temperature on the outer surface of furnace walls will drop
• 4. Energy consumption will increase

Question: A non-dimensional number generally associated with natural convection heat transfer is____________?

• 1. Prandtl number
• 2. Grashoff number
• 3. Pecelet number
• 4. Nusselt number

Question: Induction heating process is based on which of the following principles ?

• 1. Thermal ion release principle
• 2. Nucleate heating principle
• 3. Resistance heating principle
• 4. Electro-magnetic induction princi¬ple

Question: The process of heat transfer during the reentry of satellites and missiles, at very high speeds, into earth’s atmosphere is known as_______________?

• 1. ablation
• 2. radiation
• 3. viscous dissipation
• 4. irradiation

Question: In resistance heating highest working temperature is obtained from heating elements made of_____________?

• 1. nickel copper
• 2. nichrome
• 3. silicon carbide
• 4. silver

Question: For heating element high resistivity material is chosen to______________?

• 1. reduce the length of heating element
• 2. increase the life of the heating element
• 3. reduce the effect of oxidation
• 4. produce large amount of heat

Question: In the indirect resistance heating method, maximum heat-transfer takes place by____________?

• 1. radiation
• 2. convection
• 3. conduction
• 4. any of the above

Question: For intermittent work which of the following furnaces is suitable ?

• 1. Indirect arc furnace
• 2. Core less furnace
• 3. Either of the above
• 4. None of the above

Question: Induction heating takes place it which of the following ?

• 1. Insulating materials
• 2. Conducting materials which are magnetic
• 3. Conducting materials which are non-magnetic
• 4. Conducting materials which may or may not be magnetic