Question

The diagram depicts a semicircular path in which charged particles travel in the presence of a magnetic field of a mass spectrometer. If the charge of the oxygen ions are -2e and the magnetic field has a magnitude of 0.2T, how long would it take for each ion to travel the semicircular path? Note: The mass of an O2- ion is 2.6E-26kg

Answer 1

I am aware that some of the equations I should use would be
\[qvB=\frac{ mv^2 }{ r }=qE\]
But I am unsure of how to approach the problem and where to start.

Answer 2

from \(qvB=\frac{ mv^2 }{ r }\) you could say \({qB\over m}=\frac{ v }{ r }\) so \(\frac{ r }{ v } = {m\over qB}\)

and the distance the ion has to travel along the semi circle is .....???!!!

Answer 3

@IrishBoy123 piR

Answer 4

yes

\(time = \dfrac{\pi r}{v}\) and you know \(\dfrac{ r }{ v } = \dfrac{m}{qB}\)

Answer 5

so time is also equal to
\[\frac{ m \pi }{ qB}=t\]

So the first step is that the particle travels through the electric field separated by a distance d, correct? So I must first find the time traveled through the electric field (capacitor it seems?)

Answer 6

you are asked for the time taken to travel the semi circle, and that is \(\frac{ m \pi }{ qB}=t\)

i think that's it done

Answer 7

Oh duh, I kept thinking for some reason that it wanted the whole path -_-