A Hall probe (like the one you will use during labatorials to measure the magnet

Question

A Hall probe (like the one you will use during labatorials to measure the magnetic field) consists of a strip of bismuth (Bi) that is 2.0 cm long, 0.12 mm thick and 4.0 mm wide. Bismuth is a relatively poor conductor with charge carrier (electron) density n = 1.35 times 10^25m^- 3 When the probe is placed in the magnetic field, Hall voltage across the probe is 2.0 mV when the current through it is 1.25 A. HE1: Assuming the direction of carrier's motion and magnetic field is as shown in the picture, determine directions of magnetic and electric force acting on the charge. HE2: Calculate the magnetic field through the probe HE3: Determine the magnitude (and direction) of the electric field inside the Bismuth created by the excess charge on the surface.

Explanation / Answer

HE 1 :

using right hand rule , the direction of magnetic force comes out to be towards right.

for the charge carrier to pass undeflected in straight line, the electric force must be toward left and have the same magnitude as the magnetic force.

hence electric force is towards left.

HE 2 :

i = current = 1.25 A

d = thickness = 0.12 mm = 0.12 x 10-3 m

V = hall voltage = 2 mV = 0.002 Volts

n = density of mobile charges = 1.35 x 1025

Hall voltage is given as

V = i B /(n e d)

0.002 = (1.25) B/((1.35 x 1025) (1.6 x 10-19) (0.12 x 10-3))

B = 0.415 T

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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