Now, AMU is simply atomic mass unit. We're going to discuss that in detail in another lecture. But an electron has a mass of 5.5 times ten to negative four AMU that's much smaller than that of proton or a neutron. The charge, however, of a proton, an electron has the same magnitude 1.6
times ten to negative 19 Coulombs. However, the sign of a proton is positive, while the sign of an electron is negative. A neutron has VR charge.