Physics 1112
Spring 2009
University of Georgia
Instructor: HBSch¨uttler
Additional Formula Sheet for Final Exam
Reading and thoroughly familiarizing yourself with this formula sheet is an important part
of, but it is
not
a substitute for, proper exam preparation. The latter requires, among other
things, that you have reworked all assigned homework problem sets (PS) and the inclass
quizzes, studied the posted PS solutions, and worked and studied the assigned conceptual
practice (CP) problems, as well as (optionally) some practice test (PT) problems, as posted
on the LONCAPA homework and on the PHYS1112 examples and homework web pages.
You should consult the syllabus, and in particular review the Class Schedule on the last
syllabus page (posted on the PYS1112 course web site), to find out which topics you should
cover in preparing for this exam.
Induction
(1) Definition of Magnetic Flux
: For a flat surface
S
with area vector
A
normal to the
surface and finite surface area
A
≡ 
A

, subjected to a uniform magnetic field
B
, with angle
θ
≡
(
A, B
) enclosed between
A
and
B
, the magnetic flux through
S
is defined as:
Φ
m
≡
AB
cos(
θ
)
.
For surfaces
S
which are not flat and/or magnetic fields
B
which are not uniform across
S
,
Φ
m
must be calculated by: (1) breaking up
S
into smaller, (approximately) flat pieces, with
B
being (appproximately) uniform across each such surface piece; and by then: (2) adding
up the flux contributions from all these surface pieces.
(2) Faraday’s Law
: Induced voltage (EMF)
E
in a tightly wound conducting coil of
N
identical turns, with each turn enclosing the same timedependent magnetic flux Φ
m
(
t
):
E
=

N
ΔΦ
m
Δ
t
Sign Convention.
A positive EMF,
E
>
0, drives an induced current around the coil (or
would do so if the open ends of the coil were connected into a closed circuit)
in righthand
(RH) direction
around the
A
vector that was used to define the flux Φ
m
(
t
). A negative
EMF,
E
<
0, drives an induced current around the coil
against RH direction
around the
A
vector. (The RH direction around
A
is the direction of the RH 4 fingers when the RH
thumb points in
A
direction.)
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 Spring '10
 Staff
 Physics, Magnetic Field, EM wave, University of Georgia Instructor

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