J.J. Thomson and the Electron e/m Ratio

The determination of the charge-to-mass ratio (e/m) for the electron is a fundamental discovery in atomic physics.

J.J. Thomson is the scientist credited with measuring this ratio in 1897.

Key Findings

• J.J. Thomson conducted experiments using cathode ray tubes.
• He measured the deflection of cathode rays in electric and magnetic fields.
• By analyzing these deflections, he calculated the ratio of the electron's charge (e) to its mass (m).
• This measurement was crucial evidence for the electron being a fundamental particle and provided its charge-to-mass ratio, e/m = 1.7588 × 10¹¹ C/kg.

Conclusion

Therefore, J.J. Thomson determined the e/m ratio for the electron.