How are magnetic fields measured? In principle it might be possible to measure t

Question

How are magnetic fields measured? In principle it might be possible to measure the local force on a small current-carrying wire, or to attach a spring balance to a small ball of moving charge, but I expect you will have no difficulty imagining several problems with either scenario.

In practice, Hall probes, which take advantage of the Hall effect, are often used. Both the probe and the effect are named after Edwin Hall who is credited with the discovery of this effect in 1879. At its core, the physics behind the Hall effect is not any different than that of the space tether problem.

Consider the figure below. There is a simple circuit consisting of a battery, a switch, some wire, and a slab of material deliberately manufactured with a known width, length, and thickness oriented as shown. This circuit is then placed in a magnetic field directed out of the page as shown.

1)Assume that the slab of material is a conductor. For a short, but non-zero time after the switch is closed, electrons will :
Accumulate on the large flat surface that we cannot see (the back side).
Not move at all.
Travel straight through the slab of material.
Accumulate on the narrow bottom surface labeled "b".
Accumulate on the large flat surface that we can see.
Accumulate on the narrow top surface labeled "a".

2)Assume for a moment that the drift speed of the electrons in the material is 8

Explanation / Answer

B=Vh.t/A.Vd

A=2.9*7.1

So B=13.6 T

for the second one B=Vh.n.e.t/I

Vh=hall voltage=4.2 V

n=16

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.