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

A. Coreless transformers
B. Current transformers
C. Motor-generator set
D. Multi-phase transformer

A. To avoid initial rush of current
B. To avoid change in kW rating with temperature
C. Both (A) and (B)
D. Either (A) or (B)

A. Resistance heating
B. Dielectric heating
C. Arc heating
D. Induction heating

A. Thermostat
B. Thermocouple
C. Auto-transformer
D. Heating elements of variable resis-tance material

A. To achieve better heating
B. To increase the life of roof refractory
C. To have better stirring action
D. To reduce problem of oxidation
E. All of the above

A. series
B. parallel
C. series-parallel connections
D. star-delta connections
E. all of the above ways