ANSWER
[tex]2.2\cdot10^{-8}N[/tex]
EXPLANATION
The magnetic force due to the charge is given by:
[tex]\begin{gathered} F=qv\times B \\ \Rightarrow F=qvB\sin \theta \end{gathered}[/tex]
where q = electric charge
v = velocity of the charge
B = magnetic field
Therefore, substituting the given values into the equation, we have that the magnetic force due to the charge is:
[tex]\begin{gathered} F=3.5\cdot10^{-9}\cdot250\cdot25\cdot10^{-3} \\ F=2.2\cdot10^{-8}N \end{gathered}[/tex]
That is the answer.
