# ONLINE MCQ EE-Electrical Heating 6

Q41. Which of the following will happen if the thickness of refractory wall of furnace is increased ?
A.  Heat loss through furnace wall will increase
B.  Temperature inside the furnace will fall
C.  Temperature on the outer surface of furnace walls will drop
D.  Energy consumption will increase
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Q42. In an electric press mica is used
A.  as an insulator
B.  as a device for power factor im­provement
C.  for dielectric heating
D.  for induction heating
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Q43. It is desirable to operate the arc fur­naces at power factor of
A.  zero
B.  0.707 lagging
C.  unity
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Q44. Which of the following devices is necessarily required for automatic tempera­ture control in a furnace ?
A.  Thermostat
B.  Thermocouple
C.  Auto-transformer
D.  Heating elements of variable resistance material
 \$(document).ready(function(){ \$(‘#loaddata1237’).click(function(){ qid1237=\$(‘#qid1237’).val(); section1237=\$(‘#section1237’).val(); type1237=\$(‘#type1237’).val(); subtype1237=\$(‘#subtype1237’).val(); \$.post(‘../../fav’,{ qid:qid1237, section: section1237, type: type1237, subtype: subtype1237 },function(ajaxresult){ \$(‘#getrequest1237’).html(ajaxresult); qid1237=\$(‘#qid1237’).val(”); section1237=\$(‘#section1237’).val(”); type1237=\$(‘#type1237’).val(”); subtype1237=\$(‘#subtype1237’).val(”); }); }); }); Explanation:- Answer : B
Q45. Which of the following is an advantage of heating by electricity ?
A.  Quicker operation
B.  Higher efficiency
C.  Absence of flue gases
D.  All of the above
 \$(document).ready(function(){ \$(‘#loaddata1238’).click(function(){ qid1238=\$(‘#qid1238’).val(); section1238=\$(‘#section1238’).val(); type1238=\$(‘#type1238’).val(); subtype1238=\$(‘#subtype1238’).val(); \$.post(‘../../fav’,{ qid:qid1238, section: section1238, type: type1238, subtype: subtype1238 },function(ajaxresult){ \$(‘#getrequest1238’).html(ajaxresult); qid1238=\$(‘#qid1238’).val(”); section1238=\$(‘#section1238’).val(”); type1238=\$(‘#type1238’).val(”); subtype1238=\$(‘#subtype1238’).val(”); }); }); }); Explanation:- Answer : D
Q46. A perfect black body is one that
A.  transmits all incident radiations
B.  absorbs all incident radiations
C.  reflects all incident radiations
D.  absorbs, reflects and transmits all incident radiations
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Q47. The material of the heating element for a furnace should have
A.  lower melting point
B.  higher temperature co-efficient
C.  high specific resistance
D.  all of the above
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Q48. Induction heating takes place in which of the following ?
A.  Insulating materials
B.  Conducting materials which are magnetic
C.  Conducting materials which are non-magnetic
D.  Conducting materials which may or may not be magnetic
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Q49. Radiations from source,proportional to a black body are
A.  T
B.  T2
C.  T3