PRACTICE / Charged-particle circular motion

The far edge may never be reached

A particle of mass 2.0×10⁻²⁶ kg and charge +1.0×10⁻¹⁹ C enters at x=0 along +x with speed 1.0×10⁵ m/s. A uniform field B=+0.20 T along z exists only in the strip 0<x<0.12 m, with unlimited extent in y.

When does the particle first leave the strip?

1. A$\pi\ \mathrm{\mu s}$
2. B$2\pi\ \mathrm{\mu s}$
3. C$1.20\ \mathrm{\mu s}$
4. D$\pi/2\ \mathrm{\mu s}$

Try it on paper first. Free sample problems in every collection include the complete reasoning: find one in this collection →