2.2 The Heisenberg Uncertainty Principle

1

The electron cloud of an atom has a size of roughly 1 Å (Ångstrom or 10$^{-10}$ m). A nucleus has a size of about 1 fm (femtometer or fermi or 10$^{-15}$ m). A century or so ago, some people believed that each neutron in the nucleus consisted of a proton and a electron. That explained beta decay, in which the nucleus emits an electron. It also avoided the need for a third type of particle to exist besides the already known protons and electrons. Why do you believe the possibility that nuclei would contain electrons is unlikely?

2

A nano-technologist at the University of Florida claims to have developed a revolutionary technique that allows the exact measurement of linear momentum of electron pairs in a quantum dot. What do you claim?