more magnetism?

Question

A current I = 58 A flows through a strip of metal of width 6.5 cm and thickness of 0.55 mm (the figure below ). An electromagnet is switched on so that there is a uniform magnetic field of magnitude 0.61 T directed into the page, and the Hall voltage is measured to be 3.4 µV. What is the density of carriers (number of carriers per unit volume) in the strip?

Answer 1

I can't see the diagram so let me assume the Vhall is measured across the 6.5 cm direction.

Eh=3.4E-6/6.5E-2= 52.3E-6 V/m

j=58/((6.5E-2)(.55E-3))=1.62E6 A/m^2

n=jB/((Ehall)(e))=1.62E6*.61/((52.6E-6)(1.6E-19)=118E27