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Question Checkup 30.1.1: Two electrons are moving in a uniform magnetic field. One ha......

Two electrons are moving in a uniform magnetic field. One has an orbital radius of 15 cm. The other has twice the speed of the first. What is its orbital radius?

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The radius of circular motion for a charged particle in a magnetic field is given by Eq. (30.5): r=m v / q B . Since both electrons are in the same magnetic field, m, q , and B are the same, and the radius varies in proportion to the speed.Thus the second electron has twice the orbital radius of the first, or 30 cm.

r=\frac{m v}{q B}          (30.5)

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