WBJEE: Important Questions and Preparation Tips – Electromagnetic Induction
The topic Electromagnetic Induction is a very important topic from the viewpoint of WBJEE Examination. In this article, you will get chapter notes of chapter Electromagnetic Induction including important concepts, formulae and some previous year solved questions for WBJEE Entrance Examination 2018. About 1-2 questions are always asked from this topic in examination.
In this article, we bring to you concise chapter notes of chapter Electromagnetic Induction based on the latest syllabus for WBJEE Entrance Examination 2018. These notes are in very concise form and can be used for quick revision before the examination.
About the Chapter Notes:
These chapter notes are prepared by Subject Experts after the detailed analysis of some previous year papers of WBJEE Examination.
These chapter notes consist all important topics related to chapter Electromagnetic Induction like magnetic flux, Faraday’s law of induction, Lenz’s law, conservation of energy, motional and rotational electromotive force, inductance etc.
These chapter notes include important concepts, formulae and some previous year solved questions.
About the Exam:
West Bengal Joint Entrance Examination (WBJEE) is a state level common entrance test organized by West Bengal Joint Entrance Examinations Board for admission to the Undergraduate Level Engineering and Medical Courses through a common entrance test in the State of West Bengal
Some previous years solved questions are given below:
A conducting loop in the form of a circle is placed in a uniform magnetic field with its plane perpendicular to the direction of the field. An e.m.f. will be induced in the loop if
(A) it is translated parallel to itself.
(B) it is rotated about one of its diameters.
(C) it is rotated about its own axis which is parallel to the field.
(D) the loop is deformed from the original shape.
Emf will be induced in the loop only when flux changes. Now, if the loop is translated parallel to itself then there is no flux change. Hence option A is not correct.
If the loop is rotated about one of its diameters then the flux passing through loop changes so, B is correct option.
If the axis is parallel to field then again there will be no change in flux and hence no emf will be induced in the loop.
If the loop is deformed then obviously its area will change and hence the flux flowing through it will also change.
Hence, the correct options are (B) and (D).
A straight conductor 0.1m long moves in a uniform magnetic field 0.1T. The velocity of the conductor is 15 m/s and is directed perpendicular to the field. The e.m.f. induced between the two ends of the conductor is
(A) 0.10 V
(B) 0.15 V
(C) 1.50 V
(D) 15.00 V
The e.m.f. induced between the two ends of the conductor is given as:
E = Blv = 0.1×0.1×15 = 0.15V
Hence, the correct option is (B).
An electron in a circular orbit of radius .05 nm performs 1016 revolutions per second. The magnetic moment due to this rotation of electron is (in Am2)
(A) 2.16 × 10–23
(B) 3.21 × 10–22
(C) 3.21 × 10–24
(D) 1.26 × 10–23
Let the magnetic moment be M.
Hence, the correct option is (D).
Hence, the correct option is (C).