Physics 213 General Physics
description
Transcript of Physics 213 General Physics
![Page 1: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/1.jpg)
Physics 213General Physics
Lecture 9
![Page 2: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/2.jpg)
2
Exam 1: Raw Scores
0 20 40 60 80 1000
5
10
15
20
25
30
35
#
of s
tude
nts
Raw score
![Page 3: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/3.jpg)
3
Exam 1: % Scores Without Curve
0 20 40 60 80 100 120 1400
5
10
15
20
25
30
35
#
of s
tude
nts
% score without curve
![Page 4: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/4.jpg)
4
Exam 1: % Scores With Curve
0 20 40 60 80 100 120 1400
5
10
15
20
25
30
35
# of
stu
dent
s
% score with curve
%10090
2521 NN
![Page 5: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/5.jpg)
5
Last Meeting: Magnetism & Magnetic Field
Today: Lorentz Force and Torque
![Page 6: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/6.jpg)
6
![Page 7: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/7.jpg)
7
![Page 8: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/8.jpg)
8
![Page 9: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/9.jpg)
Determining the Direction of Force, the Right Hand Rule
Point your fingers in the direction of
Curl the fingers in the direction of the magnetic field,
Your thumb points in the direction of the force, , on a positive charge If the charge is negative, the
force is opposite that determined by the right hand rule
v
B
F
![Page 10: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/10.jpg)
10
┴
┴
![Page 11: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/11.jpg)
11
![Page 12: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/12.jpg)
Circular Orbit of Charged Particle in a Magnetic Field
qB
mvr
![Page 13: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/13.jpg)
Particle Moving in an External Magnetic Field
If the particle’s velocity is not perpendicular to the field, the path followed by the particle is a spiral The spiral path is
called a helix
![Page 14: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/14.jpg)
14
Force on a Wire
B is into the page The current is up
the page The force is to the
left
![Page 15: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/15.jpg)
15
Force on a Wire(cont.) B is into the page The current is
down the page The force is to the
right
![Page 16: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/16.jpg)
16
Force on a Wire The magnetic force is exerted on each moving
charge in the wire The total force is the sum of all the magnetic
forces on all the individual charges producing the current
F = B I ℓ sin θ θ is the angle between and the direction
of I The direction is found by the right hand
rule, placing your fingers in the direction of I instead of
B
v
![Page 17: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/17.jpg)
17
How is force determined?
Force on each charge carrier.
Total number of charge carriers.
Total Force
In lecture 5 we derived
sinBqvF di
nAlN
sinsin IBlBlnAqvF dtotal
dnAqvI
![Page 18: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/18.jpg)
18
![Page 19: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/19.jpg)
19
Demo Wire in Magnetic Field
![Page 20: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/20.jpg)
20
![Page 21: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/21.jpg)
21
θ
┴ θ
![Page 22: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/22.jpg)
22
Torque on a Current Loop
Applies to any shape loop
N is the number of turns in the coil
Torque has a maximum value of NBIA
When = 90° Torque is zero when the
field is perpendicular to the plane of the loop
![Page 23: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/23.jpg)
23
Motors
![Page 24: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/24.jpg)
24
┴
μ =
μ
μ θθ
![Page 25: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/25.jpg)
25
![Page 26: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/26.jpg)
26
μ
![Page 27: Physics 213 General Physics](https://reader033.fdocuments.net/reader033/viewer/2022061605/56814963550346895db6b768/html5/thumbnails/27.jpg)
27
μ
sin B