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say they dont watch the prelecture?”
say See Slide 17 Torque is always rXF
We will discuss torque for wires We will show some results for this today
20 “what does ACT stand for in lectures 10 ACTive learning segment ?
05 Confused Confident Physics 212 Lecture 14, Slide 3
Physics What is it?
What Biot-Savart Law: Fundamental law for
determining the direction and
magnitude of the magnetic field
due to an element of current
r µ0 I ds × r
4π r 2 We can use this law to calculate the magnetic field produced by ANY current distribution
Easy analytic calculations are possible only for a few distributions:
Axis of Current Loop Infinite Straight Wire
Plan for Today: Mainly use the results of these calculations!!
GOOD NEWS: Remember Gauss’ Law?
Allowed us to calculate E for
symmetrical charge distributions
:05 NEXT TIME: Introduce Ampere’s Law
Allows us to calculate B for
symmetrical current distributions
Physics 212 Lecture 14, Slide 4
Physics B from infiniter line of current
Integrating dB = µ0 I ds × r
4π r Magnitude:
µ 0 = 4 π × 10 − 7 Tm / A B Current I OUT r • r = distance from wire Direction:
Fingers: on I
curl in direction of B I Current in Wire
:07 Resulting B field Physics 212 Lecture...
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- Spring '11
- Physics, Magnetic Field, Magnetic moment, current loop