After being accelerated through a potential difference of 5.0 kV, a singly charged ¹²C⁺ ion moves in a circle of radius 21 cm in the magnetic field of a mass spectrometer. What is the magnitude of the field?

In each of these problems, the ions entering the mass spectrometer have the same charges. Except in Problem 30, the ions enter the magnetic field with equal kinetic energies (not equal speeds). Use these atomic mass values: ¹²C, 12.00 u; ¹⁴C, 14.00 u; ¹⁶O, 15.99 u. The conversion between atomic mass units and kilograms is 1 u = 1.66 × 10⁻²⁷ kg.