A charged particle moves through a velocity selector at constant velocity. The velocity selector is configured with "crossed" electric and magnetic fields of magnitude E$=2\mathrm{.}5104$N$/$C and B$=0\mathrm{.}30$T$.$ Hint

What is the velocity of the charged particle?

Velocity of the charged particle is $.$ m$/$s

When the electric field is turned off, the charged particle travels in a circular path of radius $4$mm$,$ as it travels through the magnetic field $($still at B$=0\mathrm{.}30$T$).$ What is the mass$-$to$-$charge ratio of the particle? Hint for $($b$)$

Mass$-$to$-$charge ratio of the particle is $$ kg$/$C$.$