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| Ejs Open Source Charge Particle in Electric & Magnetic Field Java Applet in 3D http://weelookang.blogspot.sg/2010/10/ejs-open-source-motion-of-charge.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSS/export/ejs_model_Chargein3DEnBfield.jar https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_users_sgeducation_lookang_Chargein3DEnBfield.jar author: lookang based on the works of andrew duffy and fu-kwun hwang |
Ejs Open Source Charge Particle in Electric & Magnetic Field Java Applet in 3D
Ejs Open Source Motion of Charge Particle in Electric & Magnetic Field in 3D
reference:
this is a remix of Charge Trajectories in 3D Electrostatic Fields Model written by Andrew Duffy http://www.compadre.org/osp/items/detail.cfm?ID=9997
with help from Charged particle motion in static Electric/Magnetic field by Fu-Kwun Hwang http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1431.0
zoom in and out graphics are taken from creative commons license http://findicons.com/icon/86740/zoom_in?width=16#
this is remixed to support content learning of small part of electromagnetism similar to Escape from Centauri 7 http://gli.lsl.nie.edu.sg/projects_centauri.html.
But the link here is about learning to be scientist
whereas the applet is more suited for inquiry learning with a shorter time frame, perhaps 1.5 hours during practical periods. hmmmmmm.
This model is created with the following 6 equations., derivation and checked by lookang
dx/dt = vx
dy/dt = vy
dz/dt = vz
dvx/dt = q*(Ex+(vy*Bz-vz*By))/m
dvy/dt = q*(Ey+(vz*Bx-vx*Bz))/m
dvz/dt = q*(Ez+(vx*By-vy*Bx))/m
Newton's 2nd Law F = ma,
because cross product is v^B in x direction is (vy*Bz-vz*By), refer to cross product literature
q*Ex + (vy*Bz-vz*By)*q = m*dvx/dt
because cross product is v^B in y direction is -(vx*Bz-vz*Bx), refer to cross product literature
q*Ey + (vz*Bx-vx*Bz)*q = m*dvy/dt
because cross product is v^B in z direction is (vx*By-vy*Bx), refer to cross product literature
q*Ez + (vx*By-vy*Bx)*q = m*dvz/dt
For 5058 PHYSICS (WITH SPA) ORDINARY LEVEL 2011
21. Electromagnetism
Content
• Magnetic effect of a current
• Applications of the magnetic effect of a current
• Force on a current-carrying conductor
• The d.c. motor
Learning Outcomes:
Candidates should be able to:
(c) describe experiments to show the force on a current-carrying conductor, and on a beam of
charged particles, in a magnetic field, including the effect of reversing
(i) the current
(ii) the direction of the field
same for 5116 SCIENCE (PHYSICS, CHEMISTRY) & 5117 SCIENCE (PHYSICS, BIOLOGY)
For This specific learning outcome, the following Activity / Exercise is suggested by lookang.
A) when velocity of charged particle is parallel to magnetic field ( Newton's 1st law of motion )
1 the simulation can be used to explore force on beam of charged particles q in a magnetic field B.
2 set the vxo = 0.6 m/s, Bx = 1 T, By = 0 T, Bz = 0 T, click on the run button to start the simulation.
3 record the path (trail left behind the particles motion) of the charged particle q.
4 record the quantities x,y,z for displacement, vx,vy,vz for instantaneous velocity and the magnetic force F_Bx, F_By,F_Bz.
5 you should move the perspective in the world view to get a better view of the motion and try to understand the motion is 3D and then 2D if it is possible to simplify.
5 set the vxo = 0.8 m/s, Bx = 1 T, By = 0 T, Bz = 0 T, click on the run button to start the simulation.
6 repeat steps 3 to 5
7 set the vxo = 1.0 m/s, Bx = 1 T, By = 0 T, Bz = 0 T, click on the run button to start the simulation.
8 repeat steps 3 to 5
9 continue to explore more vxo if necessary, and draw observable patterns or trends in path of the charged particle, record down what did you see.
hint: path is straight line, circular motion, parabolic etc?
10 now, change Bx = -1 T instead and repeat steps 2 to 9 with Bx = -1 T to explore what happens when the direction field is reverse.
11 write down what is the generalized rule when a charged particle traveling in a x direction meets a non-zero Bx field.
12 you should explore the other sliders to verify your step 11 if need.
B) when velocity of charged particle is perpendicular to magnetic field ( circular motion due to force is perpendicular to velocity )
1 the simulation can be used to explore force on beam of charged particles q in a magnetic field B.
2 set the vxo = 0.6 m/s, Bx = 0T, By = 2 T, Bz = 0 T, click on the run button to start the simulation.
3 record the path (trail left behind the particles motion) of the charged particle q.
4 record the quantities x,y,z for displacement, vx,vy,vz for instantaneous velocity and the magnetic force F_Bx, F_By,F_Bz.
5 you should move the perspective in the world view to get a better view of the motion and try to understand the motion is 3D and then 2D if it is possible to simplify.
5 set the vxo = 0.8 m/s, Bx = 0 T, By = 2 T, Bz = 0 T, click on the run button to start the simulation.
6 repeat steps 3 to 5
7 set the vxo = 1.0 m/s, Bx = 0 T, By = 2 T, Bz = 0 T, click on the run button to start the simulation.
8 repeat steps 3 to 5
9 continue to explore more vxo if necessary, and draw observable patterns or trends in path of the charged particle, record down what did you see.
hint: path is straight line, circular motion, parabolic etc?
10 now, change By = -2 T instead and repeat steps 2 to 9 with By = -2 T to explore what happens when the direction field is reverse.
11 write down what is the generalized rule when a charged particle traveling in a x direction meets a non-zero By field.
12 you should explore the other sliders to verify your step 11 if need.
C) when velocity of charged particle is perpendicular to magnetic field ( circular motion due to force is perpendicular to velocity )
1 the simulation can be used to explore force on beam of charged particles q in a magnetic field B.
2 set the vxo = 0.6 m/s, Bx = 0T, By = 0 T, Bz = 2 T, click on the run button to start the simulation.
3 record the path (trail left behind the particles motion) of the charged particle q.
4 record the quantities x,y,z for displacement, vx,vy,vz for instantaneous velocity and the magnetic force F_Bx, F_By,F_Bz.
5 you should move the perspective in the world view to get a better view of the motion and try to understand the motion is 3D and then 2D if it is possible to simplify.
5 set the vxo = 0.8 m/s, Bx = 0 T, By = 0 T, Bz = 2 T, click on the run button to start the simulation.
6 repeat steps 3 to 5
7 set the vxo = 1.0 m/s, Bx = 0 T, By = 0 T, Bz = 2 T, click on the run button to start the simulation.
8 repeat steps 3 to 5
9 continue to explore more vxo if necessary, and draw observable patterns or trends in path of the charged particle, record down what did you see.
hint: path is straight line, circular motion, parabolic etc?
10 now, change Bz = -2 T instead and repeat steps 2 to 9 with Bz = -2 T to explore what happens when the direction field is reverse.
11 write down what is the generalized rule when a charged particle traveling in a x direction meets a non-zero Bz field.
12 you should explore the other sliders to verify your step 11 if need.
Rise Above Question:
in B and C, how is the path of the charged particle different?
what can be concluded about the effect of reversing the effect of Bx.
what can be concluded about the effect of reversing the effect of By.
what can be concluded about the effect of reversing the effect of Bz.
Challenging question:
in A, B, and C the charged particle is assumed to be +1 C, what is the effect of changing q = - 1 C ?
hint: F = v^B.q where ^ is cross product.
in A, B, and C the charged particle is assumed to be +1 kg, what is the effect of changing m = + 2 kg ?
hint: Newton's 2nd Law: Fnet = m.a
set the vxo = 0 m/s, observe the resultant nmotion of q. Why did the q not move?
suggest a method to set q into motion despite when t =0 s, vxo = 0 m/s.
hint: need to explore another kind of field, called electric field!
Enjoy!
9646 H2 PHYSICS (2011) Physics Higher 1 2011 8866 only (e)
15. Electromagnetism
Content
• Force on a current-carrying conductor
• Force on a moving charge
• Magnetic fields due to currents
• Force between current-carrying conductors
Learning Outcomes
Candidates should be able to:
(e) predict the direction of the force on a charge moving in a magnetic field.
(f) recall and solve problems using F = v.B.q.sinθ.
(g) describe and analyze deflections of beams of charged particles by uniform electric and uniform magnetic fields.
(h) explain how electric and magnetic fields can be used in velocity selection for charged particles.
assume vyo = 0 m/s, vzo = 0 m/s
E
explore when vxo = 0 m/s
1 the simulation can be used to explore F_B force on beam of charged particles q in a magnetic field B.
2 set the vxo = 0 m/s, Bx = 1 T, By = 0 T, Bz = 0 T, click on the run button to start the simulation.
3 record the path (trail left behind the particles motion) of the charged particle q.
hint: it is stationary? record it
4 try other values of Bx, then follow by By, then follow by Bz.
hint: it is stationary? record it
what can be concluded about the relationship of v to F_B ?
E1 explore when vxo = 1 m/s
1 set the vxo = 1 m/s, Bx = 1 T, By = 0 T, Bz = 0 T , (optional) click on the run button to start the simulation.
2 record the direction of F_B (view the applet, as well as the column F_Bx, F_By and F_Bz to make sense)
3 try other values of Bx, then follow by By, then follow by Bz.
4 record your data systematically in a table
E2 explore when vxo = -1 m/s
1 set the vxo = -1 m/s, Bx = 1 T, By = 0 T, Bz = 0 T , (optional) click on the run button to start the simulation.
2 record the direction of F_B (view the applet, as well as the column F_Bx, F_By and F_Bz to make sense)
3 try other values of Bx, then follow by By, then follow by Bz.
4 record your data systematically in a table
E3 to scaffold the learning, verify this hypothesis that claims
F_B = v^B*q for advanced learners
or
using left hand rule, F_B (thumb) B (index finger) and i (middle finger) in 90 degree angle to each other, can be used to predict the direction of the F_B. for normal learners.
hint: direction of +i is the same as +q, because i = d(N.q)/dt
discuss with your classmates to verify this relationship.
E4 Extend this hypothesis to vxo = 0 m/s, vyo = 1 m/s, vzo = 0 m/s
vary the values of Bx = 1 T, By = 0 T, Bz = 0 T
Bx = 0 T, By = 1 T, Bz = 0 T
Bx = 0 T, By = 0 T, Bz = 1 T
can F_B = v^B*q or left hand rule, F_B (thumb) B (index finger) and i (middle finger) still predict the direction of the force?
record down the data your observed
E5 Extend this hypothesis to vxo = 0 m/s, vyo = 0 m/s, vzo = 1 m/s
vary the values of Bx = 1 T, By = 0 T, Bz = 0 T
Bx = 0 T, By = 1 T, Bz = 0 T
Bx = 0 T, By = 0 T, Bz = 1 T
can F_B = v^B*q or left hand rule, F_B (thumb) B (index finger) and i (middle finger) still predict the direction of the force?
record down the data your observed
E6 q is negative
with reference to activity E1, explore when vxo = 1 m/s
1 set the vxo = 1 m/s, Bx = 1 T, By = 0 T, Bz = 0 T , (optional) click on the run button to start the simulation.
1.5 change q to -1 C
2 record the direction of F_B (view the applet, as well as the column F_Bx, F_By and F_Bz to make sense)
3 try other values of Bx, then follow by By, then follow by Bz.
4 record your data systematically in a table
what can be concluded about the effect of q on the direction of F_B ?
how does the left hand rule stand up to this new data?
discuss how to rationalize this especially with respect to i = d(N.q)/dt
discuss with your classmates to make sense of this new data on the relationship: left hand rule, F_B (thumb) B (index finger) and i (middle finger).
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