Unformatted text preview: U = R as dV A Â· J . Show that the change in energy Î´U for a small change in J is, Î´U = Z as dV B Â· Î´ H . 5) Suppose a long solenoid of n turns/length, radius R and current I. Consider a screw driver (approximated as a cylinder with radius a such that a << R ) of permeability Î¼ partially inside the solenoid and partially outside at one end. The axis of the cylinder is parallel to that of the solenoid. What is the approximate force/area exerted on the screw driver? Is the latter pulled in or expelled? 1...
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 Spring '10
 Blecher
 Charge, Magnetism, Mass, Magnetic Field, Fundamental physics concepts, Dielectric, screw driver, magnetic potential energy, total free charge

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