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  [s]a  current-carrying  conductor,  and [/s] on  a  beam  of
charged particles, in a magnetic field, including the effect of reversing
[s](i)         the current [/s]
(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!