Question

The force needed to keep an object in circular motion is given by F= mv2/r. Combine this with F= BQv to find an expression for the magnetic flux density B needed to keep a charged particle in circular motion for a given radius r and orbital speed v.

Answer 1

$F=\frac{mv^2}{R}$ and $F=qvB$

$\frac{mv^2}{R}=qvB$

$B=\frac{v}{R(q/m)}.$