- posted
4 years ago

rot E = -d/dt B - rot(v x B)

if derived in such way it changes sign, F=-qvB.

Another two formulas can be derived from Lorentz force formula:

U=BLv; induced voltage equals induction times length times speed

F=BIL; mechanical force equals induction times current times length

both change sign, i.e. U=-BLv and F=-BIL.