Mass-to-charge ratio used as its unit in the field of mass spectrometry. Some fields use the charge-to-mass ratio ("Q"/"m") instead, which is the multiplicative inverse of the mass-to-charge ratio. The 2014 CODATA recommended value for an electron is = . When charged particles move in electric and magnetic fields the following two laws apply: where F is the force applied to the ion, "m" is the mass of the particle, a is the acceleration, "Q" is the electric charge, E is the electric field, and v × B is the cross product of the ion's velocity and the magnetic flux density. This
Charge conservation destroyed, equal numbers of positive and negative charges are destroyed. This property is supported without exception by all empirical observations so far. Although conservation of charge requires that the total quantity of charge in the universe is constant, it leaves open the question of what that quantity is. Most evidence indicates that the net charge in the universe is zero; that is, there are equal quantities of positive and negative charge. Charge conservation was first proposed by British scientist William Watson in 1746 and American statesman and scientist Benjamin Franklin in 1747, although the first convincing proof was given by