# ONLINE MCQ EE-ELECTROMAGNETIC INDUCTION 4

Q31. A 200 turn coil has an inductance of 12
mH. If the number of turns is increased
to 400 turns, all other quantities (area,
length etc.) remaining the same, the
inductance will be
A.  6 mH
B.  14 mH
C.  24 mH
D.  48 mH
 \$(document).ready(function(){ \$(‘#loaddata2130’).click(function(){ qid2130=\$(‘#qid2130’).val(); section2130=\$(‘#section2130’).val(); type2130=\$(‘#type2130’).val(); subtype2130=\$(‘#subtype2130’).val(); \$.post(‘../../fav’,{ qid:qid2130, section: section2130, type: type2130, subtype: subtype2130 },function(ajaxresult){ \$(‘#getrequest2130’).html(ajaxresult); qid2130=\$(‘#qid2130’).val(”); section2130=\$(‘#section2130’).val(”); type2130=\$(‘#type2130’).val(”); subtype2130=\$(‘#subtype2130’).val(”); }); }); }); Explanation:- Answer : D

Q32. A conductor 2 metres long moves at
right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5
m/s. The induced e.m.f. in the conductor
will be
A.  10 V
B.  15 V
C.  25 V
D.  50 V
 \$(document).ready(function(){ \$(‘#loaddata2131’).click(function(){ qid2131=\$(‘#qid2131’).val(); section2131=\$(‘#section2131’).val(); type2131=\$(‘#type2131’).val(); subtype2131=\$(‘#subtype2131’).val(); \$.post(‘../../fav’,{ qid:qid2131, section: section2131, type: type2131, subtype: subtype2131 },function(ajaxresult){ \$(‘#getrequest2131’).html(ajaxresult); qid2131=\$(‘#qid2131’).val(”); section2131=\$(‘#section2131’).val(”); type2131=\$(‘#type2131’).val(”); subtype2131=\$(‘#subtype2131’).val(”); }); }); }); Explanation:- Answer : C

Q33. A coil induces 350 mV when the current
changes at the rate of 1 A/s. The value
of inductance is
A.  3500 mH
B.  350 mH
C.  250 mH
D.  150 mH
 \$(document).ready(function(){ \$(‘#loaddata2132’).click(function(){ qid2132=\$(‘#qid2132’).val(); section2132=\$(‘#section2132’).val(); type2132=\$(‘#type2132’).val(); subtype2132=\$(‘#subtype2132’).val(); \$.post(‘../../fav’,{ qid:qid2132, section: section2132, type: type2132, subtype: subtype2132 },function(ajaxresult){ \$(‘#getrequest2132’).html(ajaxresult); qid2132=\$(‘#qid2132’).val(”); section2132=\$(‘#section2132’).val(”); type2132=\$(‘#type2132’).val(”); subtype2132=\$(‘#subtype2132’).val(”); }); }); }); Explanation:- Answer : B

Q34. As per Faraday’s laws of electromagnetic
induction, an e.m.f. is induced in
a conductor whenever it
A.  lies perpendicular to the magnetic
flux
B.  lies in a magnetic field
C.  cuts magnetic flux
D.  moves parallel to the direction of
the magnetic field
 \$(document).ready(function(){ \$(‘#loaddata2133’).click(function(){ qid2133=\$(‘#qid2133’).val(); section2133=\$(‘#section2133’).val(); type2133=\$(‘#type2133’).val(); subtype2133=\$(‘#subtype2133’).val(); \$.post(‘../../fav’,{ qid:qid2133, section: section2133, type: type2133, subtype: subtype2133 },function(ajaxresult){ \$(‘#getrequest2133’).html(ajaxresult); qid2133=\$(‘#qid2133’).val(”); section2133=\$(‘#section2133’).val(”); type2133=\$(‘#type2133’).val(”); subtype2133=\$(‘#subtype2133’).val(”); }); }); }); Explanation:- Answer : C

Q35. If current in a conductor increases then
according to Lenz’s law self-induced
voltage will
A.  aid the increasing current
B.  tend to decrease the amount of current
C.  produce current opposite to the increasing
current
D.  aid tite applied voltage
 \$(document).ready(function(){ \$(‘#loaddata2134’).click(function(){ qid2134=\$(‘#qid2134’).val(); section2134=\$(‘#section2134’).val(); type2134=\$(‘#type2134’).val(); subtype2134=\$(‘#subtype2134’).val(); \$.post(‘../../fav’,{ qid:qid2134, section: section2134, type: type2134, subtype: subtype2134 },function(ajaxresult){ \$(‘#getrequest2134’).html(ajaxresult); qid2134=\$(‘#qid2134’).val(”); section2134=\$(‘#section2134’).val(”); type2134=\$(‘#type2134’).val(”); subtype2134=\$(‘#subtype2134’).val(”); }); }); }); Explanation:- Answer : C

Q36. In case of an inductance, current is
proportional to
A.  voltage across the inductance
B.  magnetic field
C.  both (a) and (b)
D.  neither (a) nor (b)
 \$(document).ready(function(){ \$(‘#loaddata2135’).click(function(){ qid2135=\$(‘#qid2135’).val(); section2135=\$(‘#section2135’).val(); type2135=\$(‘#type2135’).val(); subtype2135=\$(‘#subtype2135’).val(); \$.post(‘../../fav’,{ qid:qid2135, section: section2135, type: type2135, subtype: subtype2135 },function(ajaxresult){ \$(‘#getrequest2135’).html(ajaxresult); qid2135=\$(‘#qid2135’).val(”); section2135=\$(‘#section2135’).val(”); type2135=\$(‘#type2135’).val(”); subtype2135=\$(‘#subtype2135’).val(”); }); }); }); Explanation:- Answer : B

Q37. Two coils have self-inductance of 10 H
and 2 H, the mutual inductance being
zero. If the two coils are connected in
series, the total inductance will be
A.  6 H
B.  8 H
C.  12 H
D.  24 H
 \$(document).ready(function(){ \$(‘#loaddata2136’).click(function(){ qid2136=\$(‘#qid2136’).val(); section2136=\$(‘#section2136’).val(); type2136=\$(‘#type2136’).val(); subtype2136=\$(‘#subtype2136’).val(); \$.post(‘../../fav’,{ qid:qid2136, section: section2136, type: type2136, subtype: subtype2136 },function(ajaxresult){ \$(‘#getrequest2136’).html(ajaxresult); qid2136=\$(‘#qid2136’).val(”); section2136=\$(‘#section2136’).val(”); type2136=\$(‘#type2136’).val(”); subtype2136=\$(‘#subtype2136’).val(”); }); }); }); Explanation:- Answer : C

Q38. Lenz’s law is a consequence of the law
of conservation of
A.  induced current
B.  charge
C.  energy
D.  induced e.m.f.
 \$(document).ready(function(){ \$(‘#loaddata2137’).click(function(){ qid2137=\$(‘#qid2137’).val(); section2137=\$(‘#section2137’).val(); type2137=\$(‘#type2137’).val(); subtype2137=\$(‘#subtype2137’).val(); \$.post(‘../../fav’,{ qid:qid2137, section: section2137, type: type2137, subtype: subtype2137 },function(ajaxresult){ \$(‘#getrequest2137’).html(ajaxresult); qid2137=\$(‘#qid2137’).val(”); section2137=\$(‘#section2137’).val(”); type2137=\$(‘#type2137’).val(”); subtype2137=\$(‘#subtype2137’).val(”); }); }); }); Explanation:- Answer : C

Q39. The property of coil by which a counter
e.m.f. is induced in it when the current
through the coil changes is known as
A.  self-inductance
B.  mutual inductance
C.  series aiding inductance
D.  capacitance
 \$(document).ready(function(){ \$(‘#loaddata2138’).click(function(){ qid2138=\$(‘#qid2138’).val(); section2138=\$(‘#section2138’).val(); type2138=\$(‘#type2138’).val(); subtype2138=\$(‘#subtype2138’).val(); \$.post(‘../../fav’,{ qid:qid2138, section: section2138, type: type2138, subtype: subtype2138 },function(ajaxresult){ \$(‘#getrequest2138’).html(ajaxresult); qid2138=\$(‘#qid2138’).val(”); section2138=\$(‘#section2138’).val(”); type2138=\$(‘#type2138’).val(”); subtype2138=\$(‘#subtype2138’).val(”); }); }); }); Explanation:- Answer : A

Q40. The direction of induced e.m.f. can be
found by
A.  Laplace’s law