Tuesday, May 27, 2008

Hello. Sorry it's late. I was looking through my binder and I remembered I wanted to be the scribe for today, so here I am.

We corrected
Physics 40S Electric and Magnetic Fields Assignment
The Physics of a Cathode Ray Tube

And here are the answers:
a. PE = QE
= (1.6 x 10-19)(20 000)
= 3.2 x 10-15 J

b. Ep = Ek
Ek = 3.2 x 10-15 J
c. KE = PE
KE = ½mv22(3.2 x 10-15)
= 9.11 x 10-31 V6.4 x 10-15 = 9.11 x 10-3 1V
8.38 x 10 7m/s = V


d. T = d/v= 0.02 8.38 x 107
= 2.39 x 10-10 s

e. E = v/d
= 500 0.01
= 500 000 m
f. a = Eq/m = (500 000)(-1.6 x 10-19) 9.11 x 10-19 kg
= -8.78 x 1016 m/s2
g. V2 = V1 + at = 0 + (8.78 X 1016)(2.39 x 10 -10)
= 2.1 x 107 m/s
h. d = 1/2 at2 = ½ (8.78 x 1016)(2.39 x 10-10)
= 2.5 x 10 -3 m

We also took some notes
Cathode Ray Tube
· electrons leave the cathode and accelerate towards the anode
· the electric field, E, alone produces a force on the electrons Fe = qE causing the elections to deflect up to x
· the magnetic field, B, alone produces a force of electrons, Fb = Bqv causing the electrons to deflect down to y


1. The Find Speed V, of electrons adjust B and E until electrons hit point z
FB = Fc
Bqv = qE
V = E/B
2. To find `m` turn off E. B will deflect electrons to y where
FB = FC
Bqv/R = mv2/BqR
3. To find charge/ratio q/m = v/BR or V = E/B

Sorry if it turned out all weird. My computer's weird, I tried. I'm weird. Okay bye.

Wednesday, May 21, 2008

i need a new computer

dang.. i hate my computer..
but.. here's my pt of view, of wat we did 2day

we pretty much started off the class w/ doing our lab. i was confused w/ wat 2 do @ 1st but hopefully ended up being partly right
the lab was fr. pg 430, i believe, fr our textbooks, & consisted of taping pennies 2 a ruler @ certain pts. Ms. K. gave us a lab worksheet 2 b handed in. Pretty sure that was all we did 2day..

next scribe...
Kevin (either one =) )

Tuesday, May 20, 2008

THE DAY AFTER...The Long Weekend

The class stared off with a short little review of the past three classes that the few who went to Moose Jaw had missed. Ms. K went over Coulomb’s Law which is basically a formula to find the electric force:

Fe = k q1 q2 / R2
(k is the only constant in this formula with is 9 x 109)


Then she also reviewed Electric Fields:

for a test charge the formula is... E = Fe / q
for a point charge the formula is... E = kQ / R2

Ms. K also reviewed some things from grade 11 on electric fields vectors and what happens to the horizontal components when you have two or more positive charges, negative charges , a positive and negative charge and also changed plates. I don’t own Adobe Photoshop so I can’t really illustrate the diagrams, but we have plenty of notes on it anyway.

After our “spectacular” review we got a new booklet called Gravitational Potential Energy which we went over in class, it shouldn’t be anything new to anyone because and Potential/Kinetic concept is the same as from past units, there’s just a different way of calculating it because we are using Electric fields. The main thing to not forget because we will be using it numerous times is the formula:
1 joules / 1 coulombs = 1 Volt

Things to look over and study from the booklet:
Electric Potential energy – scalar, joules, just energy
Electric Potential – energy / charge, scalar, joules / coulombs or VOLTs
Potential Difference – Change in potential from point 1 to another point

After that we did the Concept – Development Practice Page, and then started the Electric Potential Worksheet. And that’s the end of our class on THE DAY AFTER…the long weekend

Thursday, May 15, 2008

Thursday, May 15, 2008

Hey guys this is AznFlame and I'm the scribe for today. Well today in class we went over the Electric and Magnetic Fields handout that Ms.K gave us, we also were handed another hand out called Coulomb's Law in One Dimension we also did some problems from the green book can't remember which page though.Well that's all we did in class basically.

Next scribe will be Evan

Coulomb's Law