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21 Cards in this Set
- Front
- Back
Φ_B
magnetic flux |
Φ_B = |B|*A*cos(θ)
Φ_B (closed surface) = 0 |
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Magnetic Field Lines
-Out / In -Monopoles -Strength |
Out of North pole
Into South pole NO monopoles (make closed loops) Closer Lines = stronger field |
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Magnetic Field Facts:
(1) Sources and (2) Forces |
Sources: produced by moving charges
Forces: only "felt" by moving charges |
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MFL Symbolism
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. == out of page (point of arrow)
x == into page (tail of arrow) |
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Force on moving charge
|F| = q*|E| applied to magnetic fields |
|F| = q*|v|*|B|*sin(θ)
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Right Hand Rule
F is ┴ to B and V |
1) Finger in direction of V
2) Curl fingers in direction of B 3) Thumb points direction of F -Neg charge, opposite thumb |
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Units of Magnetic Field
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(Ns / Cm) = Tesla, "T"
Gauss = 10^-4 T |
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Charge Moving in circular path
Derive from: |a_c| = (v^2)/r Constant B |
|F| = (m*v^2)/r
qvB = (m*v^2)/r qB = (m*v)/r |
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Mass spectrometer
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Fire particles in field
-determine reaction --> mass -larger mass, larger radius |
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"Singly Ionized" particles
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q = 1*e
where e = 1.6 x 10^-19 |
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Velocity of charged particle
in a field (parallel plates) |
Find where |F_E| = |F_B|
v = |E| / |B| |
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Force on current
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|F| = I*l*B*sin(θ)
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Right Hand Rule v1.1
F is ┴ to B and I |
1) Finger in direction of I
2) Curl fingers in direction of B 3) Thumb points direction of F -Neg charge, opposite thumb |
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Torque on a circuit loop
recall: τ = F*r*sin(θ) |
τ = I*A*B*sin(θ)
1 loop = I current n loops = n(I) current |
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μ - magnetic moment vector
condensed τ equation |
μ == NIA
τ = (NIA)*B*sin(θ) τ = μ*B*sin(θ) |
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Straight and Curly rule
RHR for current Finding torque direction |
1) Curl fingers in direction of current
2) Thumb points in direction of torque |
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Magnitude of B
Given current, radius |
|B| = (μ_0)*I / 2π*r
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Constant μ_0
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Permeability of free space
μ_0 = 4πe-7 Tm/A exact --> definition |
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Straight and Curly v1.1
Finding MFL direction |
1) Point thumb straight (w/current)
2) Curl fingers to show direction of MFL's |
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Magnitude of Force
Given length of wire Given separation |
|F| = (μ_0)*I*I2*l / 2π*d
l= length of wire d = separation distance |
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Direction rule
Force on current |
1) Point fingers toward current
2) Curl in direction of B 3) Thumb points direction of force |