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Elbobo
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Homework Statement
A magnetic field of 0.1 T forces a proton beam
of 1.5 mA to move in a circle of radius 0.1 m.
The plane of the circle is perpendicular to the
magnetic field.
Of the following, which is the best estimate
of the work W done by the magnetic field on
the protons during one complete orbit of the
circle?
1. W = 0 J
2. W = 10^22 J
3. W = 10^−22 J
4. W = 10^20 J
5. W = 10^−5 J
Homework Equations
F = qVB = ILB
F = mv^2 / r
C = 2 pi*r
The Attempt at a Solution
Since work is energy, I used the formula for kinetic energy...
W = 1/2 mv^2
Fcentripetal = Fmagnetic
mv^2 /r = qvB
v = rqB / m
W = 1/2 m (rqB / m)^2
W = 1/2 (1.6725 x 10^-27) * (0.1 * 1.602 x 10^-19 * 0.1 / 1.6725 x 10^-27) ^2
W = 7.67235874 x 10^-16 J
This isn't close to any of the answer choices. Can someone help me?
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