i was reading frank shu's physical universe
lorentz's formula was given as

F=q(E + v/c x B)

whereas I know lorentz's formula to be
F= qE + qv x B
Pls explain how the first euation may have come

Question

i was reading frank shu's physical universe
lorentz's formula was given as 

F=q(E + v/c x B)

whereas I know lorentz's formula to be 
F= qE + qv x B
 Pls explain how the first euation may have come

jamesj · Answer

This is the equation of the force acting on a charge q in the presence of an electric and a magnetic field. In other words, this is classical physics and that equation is a basic one in the theory of electromagnetism. It is covered in any first course on electromagnetism--EM for short. If you are interested in learning EM, this isn't a bad place to start: http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/video-lectures/lecture-1-what-holds-our-world-together/

vincent-lyon.fr · Answer

The difference might lie in the choice of units, but it can also be a misprint in your book.