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Class XII

PHYSICS

Chapter-6-Electro Magnetic Induction

WORKSHEET-2

1. There is a uniform magnetic field directed perpendicular and into the plane of the paper. An
irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper.
Then
(a) current is induced in the loop in the anti-clockwise direction.
(b) current is induced in the loop in the clockwise direction.
(c) ac is induced in the loop.
(d) no current is induced in the loop.
2. A square of side L metres lies in the x-y plane in a region, where the magnetic field is given by B =
B0{li + 3j + 4k) T, where Bo is constant. The magnitude of flux passing through the square is
[NCERT Exemplar]
(a) 2BoL² Wb.
(b) 3BoL² Wb.
(c) 4BoL² Wb.
(d) √29 BoL² Wb.
3. An e.m.f is produced in a coil, which is not connected to an external voltage source. This is not
due to
(a) the coil being in a time varying magnetic field.
(b) the coil moving in a time varying magnetic field.
(c) the coil moving in a constant magnetic field.
(d) the coil is stationary in external spatially varying magnetic field, which does not change with
time.
4. What is the direction of induced currents in metal rings 1 and 2 when current I in the wire is
increasing steadily? [AI2017]

ANS: The direction of induced current is clockwise in metal ring 1 and anticlockwise in metal ring
2.
5. Relation between S.I. unit and C.G.S. unit of magnetic flux is _________ .

ANS: 1 Weber = 10 Maxwell
8
6. Use Lenz’s law to determine the direction of the induced current when a rectangular conducting
loop abed is moved into a region of magnetic field which is directed normal to the plane of the
loop away from the reader. [Foreign 2014]