Help me understand this derivation for hall voltage?

1. Apr 16, 2013

Turion

Derivation: http://s24.postimg.org/nhiqgg4qt/untitled.png

How did they get ΔV=Ed? (d=width of the conductor)

Sorry, I'm really rusty on my physics. Finding it quite difficult to review.

2. Apr 16, 2013

rock.freak667

Electric field strength can be defined as E = V/d.