Question

What two pieces of evidence allowed the first calculation of me, the mass of the electron?

a) Double-slit interference and photoelectric effect.

b) Diffraction of light and Compton scattering.

c) Brownian motion and ionization.

d) Ionization and the charge-to-mass ratio in a magnetic field.

Answer 1

The first calculation of the electron's mass was possible through the ionization method and the measurement of the charge-to-mass ratio in a magnetic field, not from double-slit interference experiments.

Step-by-step explanation:

The two pieces of evidence that allowed the first calculation of
`m_e`, the mass of the electron, were the ionization of gases by electrons and the determination of the charge-to-mass ratio of the electron in a magnetic field. The charge-to-mass ratio was famously measured by J.J. Thomson in 1897. Building on this, Robert Millikan's oil drop experiment in 1909 enabled the calculation of the charge of the electron. With the known charge and charge-to-mass ratio, calculating the mass of the electron was straightforward, as the charge in the equation cancels out leaving the mass of the electron.

Double-slit interference experiments and measurements like the photoelectric effect provide further insight into the behavior and properties of electrons, but they were not directly used for the initial calculation of the electron's mass. These experiments are crucial in understanding wave-particle duality and quantum mechanics.