A mass spectrometer consists of an ionization chamber in which ions are

accelerated through a potential di

erence V $=10$ kV and then are injected through

a slit into a region with uniform magnetic field B $=0\mathrm{.}1$ T$.$ After completing half a

circle, the ions are smashed into a photographic plate causing its blackening. a$)$ Find

the distance from the slit to the locations on the photographic plate where the ions $1$H$+,2$H$+,3$H$+,4$H$+$ land; b$)$ What should be the width of the slit so that one can resolve the

ions $16$O$+$ and $15$N$+?$