- Millikan determined the charge and mass on the electron through his famous Oil Drop Experiment and the values
were: e = -1.6 × 10-19 C and m = 9.1 × 10-31 kg.
- On calculation, it is found that e/m = E/H2r where E is strength of electric field. H is strength of magnetic field and r is the radius of the curved path taken up by the electron as it moves through the magnetic field.
- The value of e/m ratio for an electron is =1.78 × 108 c/g