The magnetic force is always perpendicular to the motion of

The magnetic force is always perpendicular to the motion of a charged particle, so it can\'t do any work...right? And yet, you can see electromagnets \"lift\" scrap metal in junkyards. How is that possible?

Solution

Both are two completely different mechanisms. The differences are as follows.

1) Electromagnets attracts only metals with magnetic properties while magnetic force act on any charged moving body.(metals or non-metals) according to formulae q (V X B) [right hand thumb rule)

2) Magnetic force always acts on a MOVING Charged particle rather than Non-Moving metal scraps in junkyards.

Force exerted by electromagnets are directed towards them so in this case work done is not zero.