Question

What are Helmholtz coils used for?

What quantities does the strength of the magnetic field B produced by the Helmholtz coils depend on? Which can be varied?

What affect does the Lorentz force have on the motion of electrons?

The beam of electrons you will observe is more like a thin ring, with a width. Are the electrons all moving at the same velocity? If not, are the electrons on the outer edge of the beam or the inner edge of the bem moving faster? Why?

Answer 1

A Helmholtz coil is a device for producing a region of nearly uniform magnetic field.

The strength of the magnetic field is dependent upon three quantities:

1)the current I,

2)the number of turns N in each coil, and

3) the radius a of the coil.

Current can be varied

The effect of Lorentz force is that the electrons start to move in a circle.

No, the electrons are not moving with the same velocity.

Electrons on the inner edge move faster since they have smaller radius.