Question

Consider a mass spectrometer like the one shown in the figure. A beam of singly charged positive ions is accelerated from an ion source and injected into a velocity selector with an electric field of E=2700V/m) and magnetic field of B=43.0mT. The ions then enter the deflection region where a uniform B0=39.0mT magnetic field is maintained. What is the mass of these ions if they are observed to strike a detector at a distance of 0.686m from the entrance of the deflection chamber? Answer in units of kg.