Download Blank Jeopardy

Lenz’s Law/
Transformers
Changing B
Faraday
Generators/
Motors
Induced
Current
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In 1822, Michael
Faraday wrote a goal
in his notebook:
“Convert
Magnetism
into
Electricity”
A magnetic field
can induce a
current.
Electromagnetic
Induction
The conductor,
which is often a
piece of wire, must
be ________ to the
magnetic lines of
force
Perpendicular
The direction of the
induced current is
dependent on the
relative motion of
the coil with respect
to the magnet.
The Generator
Effect
State the 4th RHR…
one used for Faraday’s
law.
-Outstretched fingers are
magnetic field
-Extended thumb is
direction wire moves
-Palm shows direction of
current flow
Changes
mechanical
energy into
electrical energy.
Generator
Coil of wire
around a soft
iron core to
concentrate
magnetic force
Armature
Changes
electrical energy
into mechanical
energy
Motor
When a generator
is connected in a
closed circuit; the
current flow is
proportional to
the _______
Electromotive
Force (EMF)
0.707 times the
maximum voltage
Effective Voltage
Even though it is
called a force, it is a
potential difference
and is measured in
volts.
Electromotive
Force (EMF)
An induced EMF
that resists the
applied EMF
Back EMF
The formula for
calculating EMF,
also state what the
variables are.
vBL
v is the velocity
B is the field
strength
L is the length of
the conductor
A permanent horseshoe magnet
is mounted so that the magnetic
field lines are vertical. If a
student passes a straight wire
between the poles and pulls it
toward herself, the current flow
through the wire is from left to
right. Which is the N – pole of
the magnet?
The top
3 Ways to
increase
EMF:
Increase the velocity
of the wire
Increase the length of
the wire
Increase the magnetic
field strength
We will use our
____ RHR
when dealing
with Lenz’s law
Second
An induced current
always flows in such a
direction as to oppose
the motion that induced
it.
Lenz’s Law
________ currents
are generated to
stop the motion of
the metal arm of a
sensitive scale.
Eddy
If a mechanical
load is placed on
the motor, slowing
it down, the back
EMF is ______.
Reduced
The N-pole of a
magnet is moved
toward the right end
of a coil. The
direction of the
induced current is?
Counter clockwise
The varying magnetic flux
is carried through the core
to the secondary coil
which induces a varying
EMF in the secondary
coil. This is called ______
________
Mutual
Inductance
A step-up transformer
increases voltage – the
current in the primary
circuit is ______ than that
in the secondary.
Greater
Upon what does the
ratio of the EMF in the
primary of a transformer
to the EMF in the
secondary of the
transformer depend?
The ratio of number of turns
of wire in the primary to the
number of turns of wire in
the secondary.
Transformer
Formula
Vs/Ns = Vp/Np
Or
Ip/Is = Vs/Ns = Vp/Np
In a transformer,
current is inversely
proportional to
______
Voltage
The power produced in
the primary coil is
______ to the power
produced in the
secondary coil.
Equal