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Name of Learner: ___________________________
Grade & Section: ___________________________
Name of School: ___________________________
12
GENERAL PHYSICS 2
2nd
Semester – Module 6
MAGNETIC FIELD AND
MAGNETIC FORCES
Republic of the Philippines
Department of Education
Regional Office IX, Zamboanga Peninsula
12
Development Team of the Module
Writer: Jeovanny A. Marticion
Editor: Zyhrine P. Mayormita
Reviewers: Leo Martinno O. Alejo, Zyhrine P. Mayormita
Layout Artist: Chris Raymund M. Bermudo
Management Team: Virgilio P. Batan Jr. - Schools Division Superintendent
Lourma I. Poculan - Asst. Schools Division Superintendent
Amelinda D. Montero - Chief Education Supervisor, CID
Nur N. Hussien - Chief Education Supervisor, SGOD
Ronillo S. Yarag - Education Program Supervisor, LRMS
Zyhrine P. Mayormita - Education Program Supervisor, Science
Leo Martinno O. Alejo- Project Development Officer II, LRMS
Joselito S. Tizon - School Principal, Zamboanga del Norte NHS
General Physics 2 - Grade 12 (STEM)
Support Material for Independent Learning Engagement (SMILE)
Module 6: Magnetic Field and Magnetic Forces
First Edition, 2021
Republic Act 8293, section176 states that: No copyright shall subsist in any work of the
Government of the Philippines. However, prior approval of the government agency or office
wherein the work is created shall be necessary for the exploitation of such work for a profit.
Such agency or office may, among other things, impose as a condition the payment of
royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names,
trademarks, etc.) included in this module are owned by their respective copyright holders.
Every effort has been exerted to locate and seek permission to use these materials from their
respective copyright owners. The publisher and authors do not represent nor claim ownership
over them.
Printed in the Philippines by
Department of Education – Region IX– Dipolog City Schools Division
Office Address: Purok Farmers, Olingan, DipologCity
Zamboanga del Norte, 7100
Telefax: (065) 212-6986 and (065)212-5818
E-mailAddress: dipolog.city@deped.gov.ph
1
What I Need to Know
This module will help you understand concepts of current, resistance,
and electromotive force. At the end of this module, you should be able to:
(1) Differentiate electric interactions from magnetic interactions
STEM_GP12EM-IIIh-54;
(2) Evaluate the total magnetic flux through an open surface
STEM_GP12EM-IIIh-55;
(3) Describe the motion of a charged particle in a magnetic field in
terms of its speed, acceleration, cyclotron radius, cyclotron
frequency, and kinetic energy STEM_GP12EM-IIIh-58;
(4) Evaluate the magnetic force on an arbitrary wire segment placed in
a uniform magnetic field STEM_GP12EM-IIIh-59;
(5) Evaluate the magnetic field vector at a given point in space due to a
moving point charge, an infinitesimal current element, or a straight
current-carrying conductor STEM_GP12EM-IIIh-60;
(6) Calculate the magnetic field due to one or more straight wire
conductors using the superposition principle STEM_GP12EM-IIIi-
62;
(7) Calculate the force per unit length on a current-carrying wire due to
the magnetic field produced by other current-carrying wires
STEM_GP12EM-IIIi-63;
(8) Evaluate the magnetic field vector at any point along the axis of a
circular current loop STEM_GP12EM-IIIi-64; and
(9) Solve problems involving magnetic fields, forces due to magnetic
fields, and the motion of charges and current-carrying wires in
contexts such as, but not limited to, determining the strength of
Earth's magnetic field, mass spectrometers, and solenoids.
STEM_GP12EM-IIIi-66
What's In
We will begin our discovery on magnetism, where most familiar
applications are always related to magnets and magnetic materials. It should
be noted that the basic characteristic of magnets was caused by the
interactions of electric charges in motion. We can say that the magnetic field
can be produced by either a magnet itself or even the current moving around
the conductor. Forces and fields will also be studied in this module, as well
as their practical applications in electric motors, TV picture tubes, particle
accelerators, magnetrons, and ovens.
2
What's New
Can we build a train without
wheels? Is it possible to build a train
that floats and glides smoothly without
touching the rail? It sounds another
science fiction, but this technology
exists now as maglev trains. The term
maglev train was derived from the word
magnetic levitation. This innovation
offers a safe, high-speed, and energy-
efficient transport system.
It started as early as the 20th
century when Robert Goddard and
Emile Bachelet proposed the concept of a floating vehicle using magnets.
Later, they were recognized as the patent owner for magnetic and levitating
trains. During the 1970s, Germany and Japan started to build research on
maglev trains. Later, German research on maglev trains was shut down.
China took the opportunity and commissioned the Germans to build the
TransRapid train in Shanghai. Shanghai maglev resulted as the high-speed
maglev train commercially used. It can carry passengers to as far as 19 miles
with a speed of 250 mph. On the other hand, Japan built the fastest bullet
trains in the world, which could run at 375 mph. Today, Japan is building
Chuo Shinkansen line, which will link Tokyo and Nagoya for only 40 minutes
compared to a 1 hour and a half trip using Tokaido Line.
Activity 1. Maglev Trains.
The figure below shows the maglev train structures (Transpid Guideway and
MLX Guideway) compared to the standard railway system.
In order to function as a maglev train, it needs the essential parts.
These are levitation, propulsion, and suspension.
The Japanese Maglev is said to be the
world’s fastest bullet train
Image source: https://www.jrailpass.com
/blog/maglev-bullet-train
3
Image Source: https://sites.tufts.edu/eeseniordesignhandbook/2015/maglev-magnetic-levitating-trains/
The train travels at 93 mph, which could build a stronger magnetic
field, allowing the train to be lifted (levitated) 4 inches off the ground. The
magnetic forces are needed for guidance, so the train moves forward and
stays at the center.
Maglev train technology holds great promises in terms of
transportation. The benefits it could offer are hard for us to deny. This
transportation breakthrough has provided us an opportunity to bring
science fiction ideas into reality.
4
(1) What makes the levitation, guidance, and suspension work?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(2) How do magnets move other magnets? Do magnets need to touch
each other?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(3) From your experience in dealing with magnetic materials, why do you
think the three elements mentioned in item 1 relate to each other?
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
________________________________________________________________________
(4) Write at least 3 advantages of building maglev trains.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
(5) Based on your prior knowledge in studying magnetism and other
related Physics concepts, cite at least 1 disadvantage of maglev trains.
Explain
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
________________________________________________________________________
(6) The Earth is said to be a magnet itself. Why is it that maglev trains
are not affected by the phenomena?
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
________________________________________________________________________
5
What Is It
Magnetic Force
A charge distribution builds an electric field E, and the field
exerted a force on every charge present. Figure 1 shows a moving
charge which creates a magnetic field around the charge and exerts a
force on any moving charge.
Figure 1. The magnetic force F action on the charge q moving with velocity v. The
vectors are perpendicular to each other.
Image source: http://www.actucation.com/college-physics-2/presence-of-only-magnetic-field
The magnetic force can then be expressed as
where F is the magnetic force in terms of Newtons (N), v is the
velocity in terms of m/s, |q| is the absolute value of the charge; v is the
velocity of the charge perpendicular to the quantities, B is the magnetic
field in terms of Tesla (T) and is the angle measured from the direction
of velocity towards the magnetic field.
Tesla = 1 T =
1 Gauss (G) = 10-4 T
The directions of the
major quantities can be
familiarized using the right-
hand rule. The thumb
represents the direction of the
velocity of the charge, the
6
middle finger represents the magnetic force, and the pointing finger
represents the magnetic field.
Figure 2. Right-Hand Rule
Image Source: https://physics.stackexchange.com/
questions/106521/force-on-a-moving-charge-in-magnetic-field
When the charge is negative, the magnetic force's direction is now
opposite to the direction given in Figure 1. Try to point the velocity in the
direction shown by the figure by turning your hand on a counterclockwise
rotation.
Figure 3. The magnetic field, force, and velocity of a negative charge
Image source: https://powerinception.com/force-on-a-current-carrying-conductor-in-a-magnetic-field.html
7
Most of the diagrams would deal with the following signs that are
usually used for the direction of magnetic forces, magnetic field, and
velocity.
Figure 4. Signs used in determining the direction of quantities
Image source: https://physics.stackexchange.com/questions/302386/confusion-regarding-plane-of-the-paper
Example 1:
A proton beam moves through a region of space where the magnetic field
is a uniform value of 2.0 T directed along the positive z-axis. The protons
have a velocity of magnitude 3.0 x 105 m/s in the xz plane at an angle of
30° to the positive z-axis. Find the force on the proton (Recall the charge
of the proton in Module 1).
A What is/are given? B = 2.0 T; v = 3.0 x 105 m/s; Ø = 30°
B What is asked? F = ?
C Are the units
consistent with the
formula?
Yes
D How will you
visualize the
problem?
E What strategy
must be employed?
We use the magnetic force formula and the RHR
30°
xz plane
Out of the Paper
or
Towards you
Into the Paper
or
Away from you
8
F Solution
( ) ( ) ( )( )
Using the right-hand rule, the middle finger points the magnetic force
along the negative y-axis while the magnetic field is along the positive
z-axis.
G What is the
conclusion?
Therefore, the force is 4.8 x 10-14 N
***Image Source: https://www.britannica.com/science/right-hand-rule-vectors
Magnetic Field Lines and Magnetic Flux
Figure 5 shows the magnetic field lines produced by different shapes
of a permanent magnet. The magnetic field of Earth is also shown in figure
6. Unlike electric field lines, the magnetic field lines do not point in the
direction of the force of charges.
Figure 5. Different shapes of permanent magnets
Image Source: https://www.britannica.com/science/magnetic-field
Figure 6. Earth's magnetic field
Image source: https://www.dkfindout.com/us/earth/structure-earth/earths-magnetic-field/
9
Magnetic flux is defined similarly to electric flux. The magnetic flux
through the surface is the amount of magnetic field lines in the surface.
This is expressed as:
The SI unit for magnetic flux is Weber (Wb).
1 Wb = 1
On the other hand, the magnetic flux density is expressed as
The SI unit for magnetic field density is 1 T =
The Motion of Charged Particles in a Magnetic Field
When a charged particle moves in a uniform magnetic field, it
follows a circular path with the initial velocity situated perpendicular to
the magnetic field. The cross sign implies that the magnetic field is
directed towards the paper.
Magnetic flux is maximum
The angle between the
field and the normal line
of the area is zero
cos 0°= 1
Magnetic flux is zero
The angle between the
field and the normal line
of the area is 90 degrees
cos 90°= 0
Magnetic flux > 0
10
Figure 7. Path of a charged particle in a uniform magnetic field
Image Source: https://profiles.uonbi.ac.ke/nyangondat/files/lesson_6_magnets_charge_in_magnetic_field.pdf
From Newton's law of motion,
Since and
Equating , we now solve for R
Magnetic Force on a Conductor
We derive the expression for the force on moving charges along the
length of a conductor given its cross-sectional area A.
11
Figure 8. Magnetic force on a current carrying conductor
Image source: https://powerinception.com/force-on-a-current-carrying-conductor-in-a-magnetic-field.html
This force can be expressed as:
where F is the magnetic force expressed in Newtons (N), I is the
current expressed in Amperes (A), l is the length expressed in meter (m),
B is the magnetic field expressed as Tesla (T) and is the angle between
the conductor and in degrees.
Example 3:
A straight wire carries a 5.0 A current from left to right in a region
between the poles of large electromagnet where a horizontal magnetic field
directed at northeast with a magnitude of 1.20 T. What is the magnitude
and direction of the force on a 1m section of a wire?
A What is/are given? I = 5.0 A; B=1.20 T at 45 degrees northeast
B What is asked?
C Are the units
consistent with the
formula?
Yes
D How will you
visualize the
problem? 45°
B
I
12
E What strategy must
be employed?
We use the magnetic force formula for
conductor
F Solution
( )( )( )
If you place your thumb and pointing finger in the direction indicated
in the paper, your middle finger will point upward in terms of
direction. This represents the magnetic force. This means the
magnetic force is towards you or out of the paper.
G What is the
conclusion?
Therefore, the force is 42.4 N directed outside the
paper.
Force and Torque on a Current Loop
Conductors carrying current are usually formed into closed loops.
The total sum of the force on the loop is just zero but the torque acting on
the loop
(recall previous module in previous quarter) has some important
properties. The figure below shows the forces on each side of the current
loop.
Figure 9. Magnetic Force in a Current Loop
. Image Source: https://www.physicskey com/torque-current-loop
13
(1) The force F on the right
side of the loop is directed
along the direction of the
positive x-axis while B is
directed along +z axis.
Confirm this with the right-
hand rule. Make sure fingers
are perpendicular to each
other.
where a represents the
length
(2) The force F is now
directed at the -y axis while
the magnetic field is directed
at +z-axis. Confirm this with
the right-hand rule. Make
sure fingers are
perpendicular to each other.
( )
where a represents the
length
(3) The force F is now
directed at -x axis. Hence, it
is -F. The magnetic field is
directed towards the -z-axis.
14
(4) The force is directed at +y-
axis. The magnetic field is
still directed at +z axis.
( )
(1) and (2) are zero due to
opposite signs and similar
magnitude while (2) and (4)
then form a couple:
The product IA represents the magnetic moment m of the loop:
We can also derive an expression for a circular loop with radius R.
This is an arrangement with a solenoid. It is a coil wound into a circular
cylinder.
where
For a solenoid with a number of N turns within a uniform field B
Example 4:
A circular coil of wire 0.0500 m in radius, having 30 turns, lies in a
horizontal plane. It carries a current of 5.00 A in a counterclockwise
rotation when viewed from above. The coil is in the magnetic field directed
towards the right with a magnitude of 1.20 T. Find the magnetic moment
and the torque on the coil.
A What is/are given? R = 0.0500 m
I = 5.00 A
B = 12.0 T
B What is asked?
C Are the units Yes
15
consistent with the
formula?
E What strategy
must be
employed?
We use the magnetic moment and the torque for
a circular loop
F Solution
We solve first for the area:
( ) ( )
Then, we plug in the value of A in the magnetic moment of the coil:
( )( )
The total magnetic moment is
( )( )
The torque of the coil is
( )( )( )
The total torque is:
( )( )
G What is the
conclusion?
Therefore, the torque and magnetic moment of the
coil with 30 turns is 1.178 Am2 and 1.41 Nm,
respectively.
The Direct-Current Motor
Electric motors are considered to be vital in modern society. The
operation of the electric motors is dependent on the conductors carrying
current. The given figure (figure 10) shows an example of a direct current
electric motor. The motor converts the electrical energy into mechanical
energy.
16
Figure 10. Direct current electric motor
Image Source: https://www.britannica.com/science/magnetic-field
Figure 11. Parts of an Electric Motor
Image Source: https://www.dukeelectric.com/electric-motor-failure/
Figure 11 shows the parts of an electric motor. The following are its
functions:
1. Stator – It a static unit that contains magnetic field windings. Its
function is to receive the supply from the power source.
2. Rotor – it is the moving part where it creates a mechanical rotation
of the unit.
3. Yoke – It is a magnetic frame made of iron or steel. This functions
as a protector. The cover keeps the inner parts of the motor safer
and helps in supporting the armature. It contains the magnetic
poles and field windings that are needed to help the field system.
4. Poles – The magnetic poles of the DC motor fit into the inner wall of
the yoke and helps them in tightening. The parts of the poles are
pole core and pole shoe. The pole core holds the pole shoe. The pole
shoe will carry the slots for the field and help in the production of
17
the flux between the rotor and stator. This also helps in reducing
the loss.
5. Brushes – This component functions with the commutator. It
functions as a bridge that will connect the static electric circuit to the
rotor.
6. Field windings – It is made of copper wire which surrounds the slots
of poles shoes. The windings are capable of forming an electromagnet
which will lead to producing flux. Effective flux cutting happens as
the rotor armature rotates within the field flux.
7. Armature Windings – The armature winding is composed of lap
winding and wave winding. The parallel paths make them different
from each other. This component is attached to the rotor and helps in
alternating the magnetic field of the path it rotates since magnetic
loss happens with respect to time.
8. DC Motor Commutator – The commutator is a split ring that is
made of copper. The operating system of the direct currents is based
on the interactive magnetic fields between the rotating armature and
the fixed stator. When the north pole of the armature is attracted to
the south pole of the stator, and vice-versa, the force is produced to
make it turn. Commutation refers to the constant torque in one
direction. The main goal of the commutation is to verify the torque
acting in the same direction. Since the voltage from the armature is
alternating, the commutator converts it into direct current. This is
where the commutator turns the coils on and off.
What's More
Activity 2: Qualitative Problems
Direction: Answer the following questions.
(1) A permanent magnet can be used to pick up a string of nails, paper
clips, or tacks, even though these are nonmagnetic materials. How can
this be?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
18
(2) How could one tell the direction of the magnetic force on a straight wire
carrying a current by just using qualitative observations?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(3) How might a loop of wire carrying a current be used as a compass?
Can it be used as a compass to distinguish the north and south?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
What I Have Learned
Activity 3: Quantitative Problem
Direction: Write your answers on a separate sheet of paper. You may also
consult your Physics teacher.
Find the unknown values of voltage and current in each resistor as shown
in the given circuit diagram:
(1) The magnetic field of a certain region has a magnitude of 1.50 T, and its
direction is along the positive x-axis, as shown in the figure below.
(a) What is the flux across the surface abcd?
(b) What is the flux across the surface befc?
(c) What is the flux across the surface aefd?
(d) What is the flux across the surface in the shaded volume?
19
Criteria 3 2 1 0
Physics
Approach
Approach is
appropriate
and complete
Approach
contains minor
errors
Some of the
concepts and
principles are
missing or
inappropriate
Solution
doesn't
indicate an
approach
Procedure Mathematical
and logical
procedures are
clear, complete
and connected
Mathematical
and logical
procedures are
missing/contain
errors
Most of the
mathematical
and logical
procedures
All
procedures
are
incomplete
and contain
errors
30 cm
50 cm
30 cm
40 cm
a
d
b
e
f
20
(2) The electron at point A in the figure below has a speed of 6 x 106 m/s.
Find the magnitude and direction of the magnetic field, which will cause the
electron to follow the semicircular path from A to B. Find the time required
for the electron to move from A to B.
Description Diagrams and
symbols used
are
appropriate
and complete
Parts of the
diagrams and
symbols contain
errors
Most of the
parts of the
diagrams and
symbols are
not useful
The entire
visualization
is wrong or
did not
include
visualization.
Criteria 3 2 1 0
Physics
Approach
Approach is
appropriate
and complete
Approach
contains minor
errors
Some of the
concepts and
principles are
missing or
inappropriate
Solution
doesn't
indicate an
approach
Procedure Mathematical
and logical
procedures
are clear,
complete and
connected
Mathematical
and logical
procedures are
missing/contain
errors
Most of the
mathematical
and logical
procedures
All
procedures
are
incomplete
and contain
errors
10 cm
A B
21
(3) A wire along the x-axis carries a current of 6.0 Ain the +x direction.
Calculate the force on a 1.00 cm section of the wire exerted by the following
magnetic fields:
a) 0.600 T in -y direction
b) 0.500 T in the +z direction
Description Diagrams and
symbols used
are
appropriate
and complete
Parts of the
diagrams and
symbols contain
errors
Most of the
parts of the
diagrams and
symbols are
not useful
The entire
visualization
is wrong or
did not
include
visualization.
22
Criteria 3 2 1 0
Physics
Approach
Approach is
appropriate
and complete
Approach
contains minor
errors
Some of the
concepts and
principles are
missing or
inappropriate
Solution
doesn't
indicate an
approach
Procedure Mathematical
and logical
procedures are
clear,
complete and
connected
Mathematical
and logical
procedures are
missing/contain
errors
Most of the
mathematical
and logical
procedures
All
procedures
are
incomplete
and contain
errors
Description Diagrams and
symbols used
are
appropriate
and complete
Parts of the
diagrams and
symbols contain
errors
Most of the
parts of the
diagrams and
symbols are
not useful
The entire
visualization
is wrong or
did not
include
visualization.
(c) 0.300 T in -x direction
23
(d) 0.200 T in the xz plane at an angle of 60 degrees from the +x axis and 30
degrees from + z-axis
Criteria 3 2 1 0
Physics
Approach
The approach
is appropriate
and complete
The approach
contains minor
errors
Some of the
concepts and
principles are
missing or
inappropriate
The solution
doesn't
indicate an
approach
Procedure Mathematical
and logical
procedures are
clear,
complete, and
connected
Mathematical
and logical
procedures are
missing/contain
errors
Most of the
mathematical
and logical
procedures
All
procedures
are
incomplete
and contain
errors
Description Diagrams and
symbols used
are appropriate
and complete
Parts of the
diagrams and
symbols contain
errors
Most of the
parts of the
diagrams and
symbols are
not useful
The entire
visualization
is wrong or
did not
include
visualization.
What I Can Do
Activity 4. Building Concept Map
Direction: Create a concept map using the concepts that you have learned
from this module. You can use words, terms, phrases, or formulas in
connecting these concepts. Refer to the scoring guide below:
Legible (easy to No (0-1) Yes (2)
24
read)
Accurate (concepts
were used
accurately)
Many
inaccuracies
(0-2)
A few
inaccuracies
(3-4)
No inaccuracies
(5)
Complete
(sufficient number
of relevant concepts
and relationships)
Limited use of
concepts
(0-2)
Some use of
concepts
(3-4)
Sufficient number
of concepts
(5)
Sophisticated
(finding meaningful
connections
between relevant
concepts)
Little or
none
(0-1)
Few
meaningful
connections
made (2-4)
Some
meaningful
connections
made (5-7)
Meaningful
and original
insights
demonstrated
(8)
Mueller's Classroom Concept Rubric
Assessment
Direction: Write the letter of your choice in the space provided.
____ 1. The magnetic fields come from
a. atoms in iron
b. permanent magnets
25
c. magnetic domains
d. moving charges
____ 2. The observer moves past a stationary electron. The instruments he
brings could only measure
a. magnetic field
b. electric field
c. both electric and magnetic field
d. any of the above
____ 3. Magnetic fields could not interact with
a. stationary charges
b. moving charges
c. stationary magnets
d. moving magnets
____ 4. The lines could give convenience in visualizing the field. Which of
the following is false?
a. the path followed by the iron particle corresponds to magnetic
field line
b. the path followed by an electric charge corresponds to an electric
field line
c. the compass needle lines up parallel to magnetic field lines
d. magnetic field lines do not exist
____ 5. A current-carrying loop tends to rotate until the plane of the loop is
a. parallel to the field
b. perpendicular to the filed
c. either parallel or perpendicular to the field
d. at a 45 degrees angle with the field
____ 6. A straight wire carries a current as shown in the figure. What is the
direction of the magnetic field?
a. upward
b. downward
c. right
d. left
____ 7. The circular loop of wire has a current running throughout the
conductor. What is the direction of the magnetic field?
a. upward
b. downward
c. into the paper
d. out of the paper
____ 8. The wire carries a current moving to the right. What is the
direction of the magnetic field?
26
a. towards you
b. away from you
c. left
d. right
____ 9. A proton passes through the region of two fixed bars of magnets.
Which is true of how it will travel in the region?
a. the path curves downward and will strike the lower magnet
b. the proton will move in a straight line
c. the path curves upwards and will strike the upper magnet
d. the proton stops and moves to left
____ 10. A student wanted to identify the poles of the three magnets by
placing the iron fillings to view the magnetic field lines. What poles
should have the same characteristic as pole E?
____ 11. The ion moves in a circular orbit of radius R in a magnetic field. If
the particle's speed is doubled, the orbit radius will be _________.
a.
b. 2R
c. R
d.4R
____ 12. The magnetic field 2 cm from a long, straight wire is 10-6 T. The
current in the wire is
a. 0.1 A
b. 100 A
c. 1000 A
d. 0.0001 A
____ 13. A 17 µC charge is moving at the speed of light (3 x 108 m/s) in the
magnetic field of 4.02 mT. What is the force on the charge?
a. 8.59 N
27
b. 290 N
c. 8.59 x 1012 N
d. 1.00 x 1016 N
____ 14. Assume that 19 cm length of wire carries a current perpendicular
to 4.1 T magnetic field and experiences a force of 7.6 mN. What is
the current in the wire?
a. 3.4 x 10-7 A
b. 9.8 x 10-3 A
c. 1.0 x 10-12 A
d. 9.8 A
____ 15. Which of the following factors will affect the strength of the
solenoid?
a. number of wraps
b. strength of current
c. wire thickness
d. core type
Additional Activities
Activity 5. Social Context
Direction: The community is a rich source for learning opportunities of
sources of direct current circuits. Choose one from the following suggested
activities in understanding the importance and utilization of electric
potential in our daily lives:
1. Conduct simulations on direct current circuits.
From this, write a short reflection. Scan the QR
code to gain access to the simulations.
2. Investigate the dent of Earth's magnetic field.
From your research, write the significant findings
and their implications in human activities.
3. Using a battery and copper wires, build an
electric motor
Image Source: https://www.education.com/science-fair/article/no-frills-motor/
28
Answer Key General Physics 2 Module 6
29
References
Printed Resources
Sears, F., Zemansky, M. and Young, H. (1992). College Physics 7th Edition. Addison-Wesley
Publishing Company
Zitzewits, Haase and Harper (2013). PHYSICS Principles and Problems. The MAcGraw-Hill
Companies, Inc.
Online References
____________. (n.d.). Actucation. Retrieved on March 2, 2021 from
http://www.actucation.com/college-physics-2/presence-of-only-magnetic-field
______________. (n.d.). Force on a Current Carrying Conductor in a Magnetic Field
_______________. (n.d.) How to Make a Simple Electric Motor. Retrieved on March 3, 2021
from https://www.education.com/science-fair/article/no-frills-motor/
15 Practice Task 2 Practice Task 3 Direction Write your ....
https://www.coursehero.com/file/p6dpeld3/15-Practice-Task-2-Practice-Task-3-
Direction-Write-your-answers-on-a-separate/
A negative bpositive cneutral ddepends on number of charges ....
https://www.coursehero.com/file/p62d2gb/anegative-bpositive-cneutral-ddepends-
on-number-of-charges-10The-electric-flux/
CHARGED PARTICLES IN A MAGNETIC FIELD.
http://spiff.rit.edu/classes/phys273/manual/em.html
DepEd Learning Portal. https://lrmds.deped.gov.ph/detail/14426
Entrancei. (2020). Magnetic force. Retrieved on March 4, 2021 from
https://www.entrancei.com/chapter-magnetics-physics-12/magnetic-force
Evaluate the total magnetic flux through an open surface ....
https://www.coursehero.com/file/p4p8m3k/Evaluate-the-total-magnetic-flux-
through-an-open-surface-Predict-the-motion-of/
Force on a Current Carrying Conductor in a Magnetic Field. Power Inception. Retrieved on
March 3, 2021 from https://powerinception.com/force-on-a-current-carrying-
conductor-in-a-magnetic-field.html
How might a loop of wire carrying a current be used as a ....
https://answers.yahoo.com/question/index?qid=20090809230258AAg9a2w
Japan Rail Pass. (2019). The Japanese Maglev: World's fastest bullet train. Retrieved on
March 1, 2021 from https://www.jrailpass.com/blog/maglev-bullet-train
K to 12 BASIC EDUCATION CURRICULUM SENIOR HIGH SCHOOL ....
https://www.deped.gov.ph/wp-content/uploads/2019/01/General-Physics-2.pdf
Magnetic Field and Forces? | Yahoo Answers.
https://ca.answers.yahoo.com/question/index?qid=20080530083452AAgVAx9
Magnetic Properties of Materials | Old is Gold | XII ....
https://tyrocity.com/question/magnetic-properties-of-materials-old-is-gold-xii/
Of a Current Element Objective Evaluate the magnetic field ....
https://www.coursehero.com/file/p63nk8q/of-a-Current-Element-Objective-
Evaluate-the-magnetic-field-vector-at-a-given/
Physics: Principles with Applications (7th Edition .... https://www.gradesaver.com
/textbooks/science/physics/physics-principles-with-applications-7th-edition/chapter-
21-electromagnetic-induction-and-faraday-s-law-problems-page-620/5
Physics1214-GeneralPhysicsII.
http://homepages.se.edu/kfrinkle/files/2015/05/Phys1214Spring2015Final.pdf
Stack Exchange Inc. (2021). Force on a moving charge in magnetic field. Physics. Retrieved
on March 3, 2021 from https://physics.stackexchange.com/questions/106521/force-
on-a-moving-charge-in-magnetic-field
Wilson, C. (n.d). Maglev: magnetic levitating trains. Electrical and computer engineering
design handbook: an introduction to electrical and computer engineering and product
design by tufts ece students. Retrieved on March 1, 2021 from
https://sites.tufts.edu/eeseniordesignhandbook/2015/maglev-magnetic-levitating-
trains/
30

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GenPhysics2_Module-6.pdf

  • 1. Name of Learner: ___________________________ Grade & Section: ___________________________ Name of School: ___________________________ 12 GENERAL PHYSICS 2 2nd Semester – Module 6 MAGNETIC FIELD AND MAGNETIC FORCES Republic of the Philippines Department of Education Regional Office IX, Zamboanga Peninsula 12
  • 2. Development Team of the Module Writer: Jeovanny A. Marticion Editor: Zyhrine P. Mayormita Reviewers: Leo Martinno O. Alejo, Zyhrine P. Mayormita Layout Artist: Chris Raymund M. Bermudo Management Team: Virgilio P. Batan Jr. - Schools Division Superintendent Lourma I. Poculan - Asst. Schools Division Superintendent Amelinda D. Montero - Chief Education Supervisor, CID Nur N. Hussien - Chief Education Supervisor, SGOD Ronillo S. Yarag - Education Program Supervisor, LRMS Zyhrine P. Mayormita - Education Program Supervisor, Science Leo Martinno O. Alejo- Project Development Officer II, LRMS Joselito S. Tizon - School Principal, Zamboanga del Norte NHS General Physics 2 - Grade 12 (STEM) Support Material for Independent Learning Engagement (SMILE) Module 6: Magnetic Field and Magnetic Forces First Edition, 2021 Republic Act 8293, section176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for the exploitation of such work for a profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Printed in the Philippines by Department of Education – Region IX– Dipolog City Schools Division Office Address: Purok Farmers, Olingan, DipologCity Zamboanga del Norte, 7100 Telefax: (065) 212-6986 and (065)212-5818 E-mailAddress: dipolog.city@deped.gov.ph
  • 3. 1 What I Need to Know This module will help you understand concepts of current, resistance, and electromotive force. At the end of this module, you should be able to: (1) Differentiate electric interactions from magnetic interactions STEM_GP12EM-IIIh-54; (2) Evaluate the total magnetic flux through an open surface STEM_GP12EM-IIIh-55; (3) Describe the motion of a charged particle in a magnetic field in terms of its speed, acceleration, cyclotron radius, cyclotron frequency, and kinetic energy STEM_GP12EM-IIIh-58; (4) Evaluate the magnetic force on an arbitrary wire segment placed in a uniform magnetic field STEM_GP12EM-IIIh-59; (5) Evaluate the magnetic field vector at a given point in space due to a moving point charge, an infinitesimal current element, or a straight current-carrying conductor STEM_GP12EM-IIIh-60; (6) Calculate the magnetic field due to one or more straight wire conductors using the superposition principle STEM_GP12EM-IIIi- 62; (7) Calculate the force per unit length on a current-carrying wire due to the magnetic field produced by other current-carrying wires STEM_GP12EM-IIIi-63; (8) Evaluate the magnetic field vector at any point along the axis of a circular current loop STEM_GP12EM-IIIi-64; and (9) Solve problems involving magnetic fields, forces due to magnetic fields, and the motion of charges and current-carrying wires in contexts such as, but not limited to, determining the strength of Earth's magnetic field, mass spectrometers, and solenoids. STEM_GP12EM-IIIi-66 What's In We will begin our discovery on magnetism, where most familiar applications are always related to magnets and magnetic materials. It should be noted that the basic characteristic of magnets was caused by the interactions of electric charges in motion. We can say that the magnetic field can be produced by either a magnet itself or even the current moving around the conductor. Forces and fields will also be studied in this module, as well as their practical applications in electric motors, TV picture tubes, particle accelerators, magnetrons, and ovens.
  • 4. 2 What's New Can we build a train without wheels? Is it possible to build a train that floats and glides smoothly without touching the rail? It sounds another science fiction, but this technology exists now as maglev trains. The term maglev train was derived from the word magnetic levitation. This innovation offers a safe, high-speed, and energy- efficient transport system. It started as early as the 20th century when Robert Goddard and Emile Bachelet proposed the concept of a floating vehicle using magnets. Later, they were recognized as the patent owner for magnetic and levitating trains. During the 1970s, Germany and Japan started to build research on maglev trains. Later, German research on maglev trains was shut down. China took the opportunity and commissioned the Germans to build the TransRapid train in Shanghai. Shanghai maglev resulted as the high-speed maglev train commercially used. It can carry passengers to as far as 19 miles with a speed of 250 mph. On the other hand, Japan built the fastest bullet trains in the world, which could run at 375 mph. Today, Japan is building Chuo Shinkansen line, which will link Tokyo and Nagoya for only 40 minutes compared to a 1 hour and a half trip using Tokaido Line. Activity 1. Maglev Trains. The figure below shows the maglev train structures (Transpid Guideway and MLX Guideway) compared to the standard railway system. In order to function as a maglev train, it needs the essential parts. These are levitation, propulsion, and suspension. The Japanese Maglev is said to be the world’s fastest bullet train Image source: https://www.jrailpass.com /blog/maglev-bullet-train
  • 5. 3 Image Source: https://sites.tufts.edu/eeseniordesignhandbook/2015/maglev-magnetic-levitating-trains/ The train travels at 93 mph, which could build a stronger magnetic field, allowing the train to be lifted (levitated) 4 inches off the ground. The magnetic forces are needed for guidance, so the train moves forward and stays at the center. Maglev train technology holds great promises in terms of transportation. The benefits it could offer are hard for us to deny. This transportation breakthrough has provided us an opportunity to bring science fiction ideas into reality.
  • 6. 4 (1) What makes the levitation, guidance, and suspension work? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ (2) How do magnets move other magnets? Do magnets need to touch each other? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ (3) From your experience in dealing with magnetic materials, why do you think the three elements mentioned in item 1 relate to each other? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ ________________________________________________________________________ (4) Write at least 3 advantages of building maglev trains. _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ (5) Based on your prior knowledge in studying magnetism and other related Physics concepts, cite at least 1 disadvantage of maglev trains. Explain ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ________________________________________________________________________ (6) The Earth is said to be a magnet itself. Why is it that maglev trains are not affected by the phenomena? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ ________________________________________________________________________
  • 7. 5 What Is It Magnetic Force A charge distribution builds an electric field E, and the field exerted a force on every charge present. Figure 1 shows a moving charge which creates a magnetic field around the charge and exerts a force on any moving charge. Figure 1. The magnetic force F action on the charge q moving with velocity v. The vectors are perpendicular to each other. Image source: http://www.actucation.com/college-physics-2/presence-of-only-magnetic-field The magnetic force can then be expressed as where F is the magnetic force in terms of Newtons (N), v is the velocity in terms of m/s, |q| is the absolute value of the charge; v is the velocity of the charge perpendicular to the quantities, B is the magnetic field in terms of Tesla (T) and is the angle measured from the direction of velocity towards the magnetic field. Tesla = 1 T = 1 Gauss (G) = 10-4 T The directions of the major quantities can be familiarized using the right- hand rule. The thumb represents the direction of the velocity of the charge, the
  • 8. 6 middle finger represents the magnetic force, and the pointing finger represents the magnetic field. Figure 2. Right-Hand Rule Image Source: https://physics.stackexchange.com/ questions/106521/force-on-a-moving-charge-in-magnetic-field When the charge is negative, the magnetic force's direction is now opposite to the direction given in Figure 1. Try to point the velocity in the direction shown by the figure by turning your hand on a counterclockwise rotation. Figure 3. The magnetic field, force, and velocity of a negative charge Image source: https://powerinception.com/force-on-a-current-carrying-conductor-in-a-magnetic-field.html
  • 9. 7 Most of the diagrams would deal with the following signs that are usually used for the direction of magnetic forces, magnetic field, and velocity. Figure 4. Signs used in determining the direction of quantities Image source: https://physics.stackexchange.com/questions/302386/confusion-regarding-plane-of-the-paper Example 1: A proton beam moves through a region of space where the magnetic field is a uniform value of 2.0 T directed along the positive z-axis. The protons have a velocity of magnitude 3.0 x 105 m/s in the xz plane at an angle of 30° to the positive z-axis. Find the force on the proton (Recall the charge of the proton in Module 1). A What is/are given? B = 2.0 T; v = 3.0 x 105 m/s; Ø = 30° B What is asked? F = ? C Are the units consistent with the formula? Yes D How will you visualize the problem? E What strategy must be employed? We use the magnetic force formula and the RHR 30° xz plane Out of the Paper or Towards you Into the Paper or Away from you
  • 10. 8 F Solution ( ) ( ) ( )( ) Using the right-hand rule, the middle finger points the magnetic force along the negative y-axis while the magnetic field is along the positive z-axis. G What is the conclusion? Therefore, the force is 4.8 x 10-14 N ***Image Source: https://www.britannica.com/science/right-hand-rule-vectors Magnetic Field Lines and Magnetic Flux Figure 5 shows the magnetic field lines produced by different shapes of a permanent magnet. The magnetic field of Earth is also shown in figure 6. Unlike electric field lines, the magnetic field lines do not point in the direction of the force of charges. Figure 5. Different shapes of permanent magnets Image Source: https://www.britannica.com/science/magnetic-field Figure 6. Earth's magnetic field Image source: https://www.dkfindout.com/us/earth/structure-earth/earths-magnetic-field/
  • 11. 9 Magnetic flux is defined similarly to electric flux. The magnetic flux through the surface is the amount of magnetic field lines in the surface. This is expressed as: The SI unit for magnetic flux is Weber (Wb). 1 Wb = 1 On the other hand, the magnetic flux density is expressed as The SI unit for magnetic field density is 1 T = The Motion of Charged Particles in a Magnetic Field When a charged particle moves in a uniform magnetic field, it follows a circular path with the initial velocity situated perpendicular to the magnetic field. The cross sign implies that the magnetic field is directed towards the paper. Magnetic flux is maximum The angle between the field and the normal line of the area is zero cos 0°= 1 Magnetic flux is zero The angle between the field and the normal line of the area is 90 degrees cos 90°= 0 Magnetic flux > 0
  • 12. 10 Figure 7. Path of a charged particle in a uniform magnetic field Image Source: https://profiles.uonbi.ac.ke/nyangondat/files/lesson_6_magnets_charge_in_magnetic_field.pdf From Newton's law of motion, Since and Equating , we now solve for R Magnetic Force on a Conductor We derive the expression for the force on moving charges along the length of a conductor given its cross-sectional area A.
  • 13. 11 Figure 8. Magnetic force on a current carrying conductor Image source: https://powerinception.com/force-on-a-current-carrying-conductor-in-a-magnetic-field.html This force can be expressed as: where F is the magnetic force expressed in Newtons (N), I is the current expressed in Amperes (A), l is the length expressed in meter (m), B is the magnetic field expressed as Tesla (T) and is the angle between the conductor and in degrees. Example 3: A straight wire carries a 5.0 A current from left to right in a region between the poles of large electromagnet where a horizontal magnetic field directed at northeast with a magnitude of 1.20 T. What is the magnitude and direction of the force on a 1m section of a wire? A What is/are given? I = 5.0 A; B=1.20 T at 45 degrees northeast B What is asked? C Are the units consistent with the formula? Yes D How will you visualize the problem? 45° B I
  • 14. 12 E What strategy must be employed? We use the magnetic force formula for conductor F Solution ( )( )( ) If you place your thumb and pointing finger in the direction indicated in the paper, your middle finger will point upward in terms of direction. This represents the magnetic force. This means the magnetic force is towards you or out of the paper. G What is the conclusion? Therefore, the force is 42.4 N directed outside the paper. Force and Torque on a Current Loop Conductors carrying current are usually formed into closed loops. The total sum of the force on the loop is just zero but the torque acting on the loop (recall previous module in previous quarter) has some important properties. The figure below shows the forces on each side of the current loop. Figure 9. Magnetic Force in a Current Loop . Image Source: https://www.physicskey com/torque-current-loop
  • 15. 13 (1) The force F on the right side of the loop is directed along the direction of the positive x-axis while B is directed along +z axis. Confirm this with the right- hand rule. Make sure fingers are perpendicular to each other. where a represents the length (2) The force F is now directed at the -y axis while the magnetic field is directed at +z-axis. Confirm this with the right-hand rule. Make sure fingers are perpendicular to each other. ( ) where a represents the length (3) The force F is now directed at -x axis. Hence, it is -F. The magnetic field is directed towards the -z-axis.
  • 16. 14 (4) The force is directed at +y- axis. The magnetic field is still directed at +z axis. ( ) (1) and (2) are zero due to opposite signs and similar magnitude while (2) and (4) then form a couple: The product IA represents the magnetic moment m of the loop: We can also derive an expression for a circular loop with radius R. This is an arrangement with a solenoid. It is a coil wound into a circular cylinder. where For a solenoid with a number of N turns within a uniform field B Example 4: A circular coil of wire 0.0500 m in radius, having 30 turns, lies in a horizontal plane. It carries a current of 5.00 A in a counterclockwise rotation when viewed from above. The coil is in the magnetic field directed towards the right with a magnitude of 1.20 T. Find the magnetic moment and the torque on the coil. A What is/are given? R = 0.0500 m I = 5.00 A B = 12.0 T B What is asked? C Are the units Yes
  • 17. 15 consistent with the formula? E What strategy must be employed? We use the magnetic moment and the torque for a circular loop F Solution We solve first for the area: ( ) ( ) Then, we plug in the value of A in the magnetic moment of the coil: ( )( ) The total magnetic moment is ( )( ) The torque of the coil is ( )( )( ) The total torque is: ( )( ) G What is the conclusion? Therefore, the torque and magnetic moment of the coil with 30 turns is 1.178 Am2 and 1.41 Nm, respectively. The Direct-Current Motor Electric motors are considered to be vital in modern society. The operation of the electric motors is dependent on the conductors carrying current. The given figure (figure 10) shows an example of a direct current electric motor. The motor converts the electrical energy into mechanical energy.
  • 18. 16 Figure 10. Direct current electric motor Image Source: https://www.britannica.com/science/magnetic-field Figure 11. Parts of an Electric Motor Image Source: https://www.dukeelectric.com/electric-motor-failure/ Figure 11 shows the parts of an electric motor. The following are its functions: 1. Stator – It a static unit that contains magnetic field windings. Its function is to receive the supply from the power source. 2. Rotor – it is the moving part where it creates a mechanical rotation of the unit. 3. Yoke – It is a magnetic frame made of iron or steel. This functions as a protector. The cover keeps the inner parts of the motor safer and helps in supporting the armature. It contains the magnetic poles and field windings that are needed to help the field system. 4. Poles – The magnetic poles of the DC motor fit into the inner wall of the yoke and helps them in tightening. The parts of the poles are pole core and pole shoe. The pole core holds the pole shoe. The pole shoe will carry the slots for the field and help in the production of
  • 19. 17 the flux between the rotor and stator. This also helps in reducing the loss. 5. Brushes – This component functions with the commutator. It functions as a bridge that will connect the static electric circuit to the rotor. 6. Field windings – It is made of copper wire which surrounds the slots of poles shoes. The windings are capable of forming an electromagnet which will lead to producing flux. Effective flux cutting happens as the rotor armature rotates within the field flux. 7. Armature Windings – The armature winding is composed of lap winding and wave winding. The parallel paths make them different from each other. This component is attached to the rotor and helps in alternating the magnetic field of the path it rotates since magnetic loss happens with respect to time. 8. DC Motor Commutator – The commutator is a split ring that is made of copper. The operating system of the direct currents is based on the interactive magnetic fields between the rotating armature and the fixed stator. When the north pole of the armature is attracted to the south pole of the stator, and vice-versa, the force is produced to make it turn. Commutation refers to the constant torque in one direction. The main goal of the commutation is to verify the torque acting in the same direction. Since the voltage from the armature is alternating, the commutator converts it into direct current. This is where the commutator turns the coils on and off. What's More Activity 2: Qualitative Problems Direction: Answer the following questions. (1) A permanent magnet can be used to pick up a string of nails, paper clips, or tacks, even though these are nonmagnetic materials. How can this be? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________
  • 20. 18 (2) How could one tell the direction of the magnetic force on a straight wire carrying a current by just using qualitative observations? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ (3) How might a loop of wire carrying a current be used as a compass? Can it be used as a compass to distinguish the north and south? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ What I Have Learned Activity 3: Quantitative Problem Direction: Write your answers on a separate sheet of paper. You may also consult your Physics teacher. Find the unknown values of voltage and current in each resistor as shown in the given circuit diagram: (1) The magnetic field of a certain region has a magnitude of 1.50 T, and its direction is along the positive x-axis, as shown in the figure below. (a) What is the flux across the surface abcd? (b) What is the flux across the surface befc? (c) What is the flux across the surface aefd? (d) What is the flux across the surface in the shaded volume?
  • 21. 19 Criteria 3 2 1 0 Physics Approach Approach is appropriate and complete Approach contains minor errors Some of the concepts and principles are missing or inappropriate Solution doesn't indicate an approach Procedure Mathematical and logical procedures are clear, complete and connected Mathematical and logical procedures are missing/contain errors Most of the mathematical and logical procedures All procedures are incomplete and contain errors 30 cm 50 cm 30 cm 40 cm a d b e f
  • 22. 20 (2) The electron at point A in the figure below has a speed of 6 x 106 m/s. Find the magnitude and direction of the magnetic field, which will cause the electron to follow the semicircular path from A to B. Find the time required for the electron to move from A to B. Description Diagrams and symbols used are appropriate and complete Parts of the diagrams and symbols contain errors Most of the parts of the diagrams and symbols are not useful The entire visualization is wrong or did not include visualization. Criteria 3 2 1 0 Physics Approach Approach is appropriate and complete Approach contains minor errors Some of the concepts and principles are missing or inappropriate Solution doesn't indicate an approach Procedure Mathematical and logical procedures are clear, complete and connected Mathematical and logical procedures are missing/contain errors Most of the mathematical and logical procedures All procedures are incomplete and contain errors 10 cm A B
  • 23. 21 (3) A wire along the x-axis carries a current of 6.0 Ain the +x direction. Calculate the force on a 1.00 cm section of the wire exerted by the following magnetic fields: a) 0.600 T in -y direction b) 0.500 T in the +z direction Description Diagrams and symbols used are appropriate and complete Parts of the diagrams and symbols contain errors Most of the parts of the diagrams and symbols are not useful The entire visualization is wrong or did not include visualization.
  • 24. 22 Criteria 3 2 1 0 Physics Approach Approach is appropriate and complete Approach contains minor errors Some of the concepts and principles are missing or inappropriate Solution doesn't indicate an approach Procedure Mathematical and logical procedures are clear, complete and connected Mathematical and logical procedures are missing/contain errors Most of the mathematical and logical procedures All procedures are incomplete and contain errors Description Diagrams and symbols used are appropriate and complete Parts of the diagrams and symbols contain errors Most of the parts of the diagrams and symbols are not useful The entire visualization is wrong or did not include visualization. (c) 0.300 T in -x direction
  • 25. 23 (d) 0.200 T in the xz plane at an angle of 60 degrees from the +x axis and 30 degrees from + z-axis Criteria 3 2 1 0 Physics Approach The approach is appropriate and complete The approach contains minor errors Some of the concepts and principles are missing or inappropriate The solution doesn't indicate an approach Procedure Mathematical and logical procedures are clear, complete, and connected Mathematical and logical procedures are missing/contain errors Most of the mathematical and logical procedures All procedures are incomplete and contain errors Description Diagrams and symbols used are appropriate and complete Parts of the diagrams and symbols contain errors Most of the parts of the diagrams and symbols are not useful The entire visualization is wrong or did not include visualization. What I Can Do Activity 4. Building Concept Map Direction: Create a concept map using the concepts that you have learned from this module. You can use words, terms, phrases, or formulas in connecting these concepts. Refer to the scoring guide below: Legible (easy to No (0-1) Yes (2)
  • 26. 24 read) Accurate (concepts were used accurately) Many inaccuracies (0-2) A few inaccuracies (3-4) No inaccuracies (5) Complete (sufficient number of relevant concepts and relationships) Limited use of concepts (0-2) Some use of concepts (3-4) Sufficient number of concepts (5) Sophisticated (finding meaningful connections between relevant concepts) Little or none (0-1) Few meaningful connections made (2-4) Some meaningful connections made (5-7) Meaningful and original insights demonstrated (8) Mueller's Classroom Concept Rubric Assessment Direction: Write the letter of your choice in the space provided. ____ 1. The magnetic fields come from a. atoms in iron b. permanent magnets
  • 27. 25 c. magnetic domains d. moving charges ____ 2. The observer moves past a stationary electron. The instruments he brings could only measure a. magnetic field b. electric field c. both electric and magnetic field d. any of the above ____ 3. Magnetic fields could not interact with a. stationary charges b. moving charges c. stationary magnets d. moving magnets ____ 4. The lines could give convenience in visualizing the field. Which of the following is false? a. the path followed by the iron particle corresponds to magnetic field line b. the path followed by an electric charge corresponds to an electric field line c. the compass needle lines up parallel to magnetic field lines d. magnetic field lines do not exist ____ 5. A current-carrying loop tends to rotate until the plane of the loop is a. parallel to the field b. perpendicular to the filed c. either parallel or perpendicular to the field d. at a 45 degrees angle with the field ____ 6. A straight wire carries a current as shown in the figure. What is the direction of the magnetic field? a. upward b. downward c. right d. left ____ 7. The circular loop of wire has a current running throughout the conductor. What is the direction of the magnetic field? a. upward b. downward c. into the paper d. out of the paper ____ 8. The wire carries a current moving to the right. What is the direction of the magnetic field?
  • 28. 26 a. towards you b. away from you c. left d. right ____ 9. A proton passes through the region of two fixed bars of magnets. Which is true of how it will travel in the region? a. the path curves downward and will strike the lower magnet b. the proton will move in a straight line c. the path curves upwards and will strike the upper magnet d. the proton stops and moves to left ____ 10. A student wanted to identify the poles of the three magnets by placing the iron fillings to view the magnetic field lines. What poles should have the same characteristic as pole E? ____ 11. The ion moves in a circular orbit of radius R in a magnetic field. If the particle's speed is doubled, the orbit radius will be _________. a. b. 2R c. R d.4R ____ 12. The magnetic field 2 cm from a long, straight wire is 10-6 T. The current in the wire is a. 0.1 A b. 100 A c. 1000 A d. 0.0001 A ____ 13. A 17 µC charge is moving at the speed of light (3 x 108 m/s) in the magnetic field of 4.02 mT. What is the force on the charge? a. 8.59 N
  • 29. 27 b. 290 N c. 8.59 x 1012 N d. 1.00 x 1016 N ____ 14. Assume that 19 cm length of wire carries a current perpendicular to 4.1 T magnetic field and experiences a force of 7.6 mN. What is the current in the wire? a. 3.4 x 10-7 A b. 9.8 x 10-3 A c. 1.0 x 10-12 A d. 9.8 A ____ 15. Which of the following factors will affect the strength of the solenoid? a. number of wraps b. strength of current c. wire thickness d. core type Additional Activities Activity 5. Social Context Direction: The community is a rich source for learning opportunities of sources of direct current circuits. Choose one from the following suggested activities in understanding the importance and utilization of electric potential in our daily lives: 1. Conduct simulations on direct current circuits. From this, write a short reflection. Scan the QR code to gain access to the simulations. 2. Investigate the dent of Earth's magnetic field. From your research, write the significant findings and their implications in human activities. 3. Using a battery and copper wires, build an electric motor Image Source: https://www.education.com/science-fair/article/no-frills-motor/
  • 30. 28 Answer Key General Physics 2 Module 6
  • 31. 29 References Printed Resources Sears, F., Zemansky, M. and Young, H. (1992). College Physics 7th Edition. Addison-Wesley Publishing Company Zitzewits, Haase and Harper (2013). PHYSICS Principles and Problems. The MAcGraw-Hill Companies, Inc. Online References ____________. (n.d.). Actucation. Retrieved on March 2, 2021 from http://www.actucation.com/college-physics-2/presence-of-only-magnetic-field ______________. (n.d.). Force on a Current Carrying Conductor in a Magnetic Field _______________. (n.d.) How to Make a Simple Electric Motor. Retrieved on March 3, 2021 from https://www.education.com/science-fair/article/no-frills-motor/ 15 Practice Task 2 Practice Task 3 Direction Write your .... https://www.coursehero.com/file/p6dpeld3/15-Practice-Task-2-Practice-Task-3- Direction-Write-your-answers-on-a-separate/ A negative bpositive cneutral ddepends on number of charges .... https://www.coursehero.com/file/p62d2gb/anegative-bpositive-cneutral-ddepends- on-number-of-charges-10The-electric-flux/ CHARGED PARTICLES IN A MAGNETIC FIELD. http://spiff.rit.edu/classes/phys273/manual/em.html DepEd Learning Portal. https://lrmds.deped.gov.ph/detail/14426 Entrancei. (2020). Magnetic force. Retrieved on March 4, 2021 from https://www.entrancei.com/chapter-magnetics-physics-12/magnetic-force Evaluate the total magnetic flux through an open surface .... https://www.coursehero.com/file/p4p8m3k/Evaluate-the-total-magnetic-flux- through-an-open-surface-Predict-the-motion-of/ Force on a Current Carrying Conductor in a Magnetic Field. Power Inception. Retrieved on March 3, 2021 from https://powerinception.com/force-on-a-current-carrying- conductor-in-a-magnetic-field.html How might a loop of wire carrying a current be used as a .... https://answers.yahoo.com/question/index?qid=20090809230258AAg9a2w Japan Rail Pass. (2019). The Japanese Maglev: World's fastest bullet train. Retrieved on March 1, 2021 from https://www.jrailpass.com/blog/maglev-bullet-train K to 12 BASIC EDUCATION CURRICULUM SENIOR HIGH SCHOOL .... https://www.deped.gov.ph/wp-content/uploads/2019/01/General-Physics-2.pdf Magnetic Field and Forces? | Yahoo Answers. https://ca.answers.yahoo.com/question/index?qid=20080530083452AAgVAx9 Magnetic Properties of Materials | Old is Gold | XII .... https://tyrocity.com/question/magnetic-properties-of-materials-old-is-gold-xii/ Of a Current Element Objective Evaluate the magnetic field .... https://www.coursehero.com/file/p63nk8q/of-a-Current-Element-Objective- Evaluate-the-magnetic-field-vector-at-a-given/ Physics: Principles with Applications (7th Edition .... https://www.gradesaver.com /textbooks/science/physics/physics-principles-with-applications-7th-edition/chapter- 21-electromagnetic-induction-and-faraday-s-law-problems-page-620/5 Physics1214-GeneralPhysicsII. http://homepages.se.edu/kfrinkle/files/2015/05/Phys1214Spring2015Final.pdf Stack Exchange Inc. (2021). Force on a moving charge in magnetic field. Physics. Retrieved on March 3, 2021 from https://physics.stackexchange.com/questions/106521/force- on-a-moving-charge-in-magnetic-field Wilson, C. (n.d). Maglev: magnetic levitating trains. Electrical and computer engineering design handbook: an introduction to electrical and computer engineering and product design by tufts ece students. Retrieved on March 1, 2021 from https://sites.tufts.edu/eeseniordesignhandbook/2015/maglev-magnetic-levitating- trains/
  • 32. 30