Question

In Thomson's experiments with electron beams, when the magnetic force FM balanced the force of the electric field Fe, the velocity of the beam was given by the ratio--- divided by--- .

Answer 1

E

B

Step-by-step explanation:

Answer 2

In Thomson's experiment, when the magnetic force balanced the electric force, the velocity of the beam was

`v= (E)/(B)`
where E is the magnitude of the electric field and B the magnitude of the magnetic field.

Let's see why. The force exerted by the electric field of intensity E on each electron is

`F=eE`
where
`e` is the electron charge.
The force exerted by the magnetic field of intensity B on each electron is

`F=evB`
where v is the speed of the electrons.

When the two forces are balanced, we have:

`eE=evB`
from which we find

`v= (E)/(B)`