Experiments were carried out in which a beam of cathode rays was first bent by a magnetic field and then bent back by an electrostatic field until the beam hit the screen exactly where it had been hitting before the fields were applied.This experiment permitted the direct measurement of
A)the ratio of mass to charge of an electron.
B)the charge on the nucleus of an atom.
C)the charge on the electron.
D)the mass of the atom.
E)the mass of the electron.

Question

Quizplus · Accepted Answer

By measuring the amount of magnetic and electrostatic force required to bend the beam back to its original position, the ratio of the mass of the electron to its charge (e/m) can be calculated. This experiment is known as the Thomson experiment and is one of the earliest experiments to measure the properties of the electron.

Experiments Were Carried Out in Which a Beam of Cathode