in this example, the figure shows a circular
coil of radius ay and resistance r, placed
in a uniform magnetic induction b. if the
coil is rotated about the diametrical axis
by 1 80 degrees, we’ve to find the amount
of charge flown through the coil. in this
situation, we can directly use the result
that, in any situation, or change in orientation
of the coil in magnetic field, charge flown,
through coil can be directly given as, delta
q as mod of, delta phi by r. now, if we calculate,
the initial flux, through coil, this can be
given as, b pi ay square, as it is b dot ay.
and if the coil is rotated by 1 80 degrees,
say if area vector initially was in inward
direction on rotating it’ll come out in
upward direction.
so we can write, final flux, through coil,
this final flux we can write as, minus b pi
ay square because, finally the direction of
area vector and magnetic induction are opposite.
from this if we calculate the magnitude of
change in flux, this can be written as 2 b
pi ay square.
so here charge flown, through the coil can
directly be given as delta q is, 2 b pi, ay
square divided by r. that’ll be the answer
to this problem.
