Answer the following questions:
(a) Quarks inside protons and neutrons are thought to carry fractional charges
\([(+2 / 3) e ;(-1 / 3) e] .\) Why do they not show up in Millikan's oil-drop
experiment?
(b) What is so special about the combination \(e / m ?\) Why do we not simply
talk of \(e\) and \(m\) separately?
(c) Why should gases be insulators at ordinary pressures and start conducting
at very low pressures?
(d) Every metal has a definite work function. Why do all photoelectrons not
come out with the same energy if incident radiation is monochromatic? Why is
there an energy distribution of photoelectrons?
(e) The energy and momentum of an electron are related to the frequency and
wavelength of the associated matter wave by the relations:
\(E=h v, p=\frac{h}{\lambda}\)
But while the value of \(\lambda\) is physically significant, the value of \(v\)
(and therefore, the value of the phase speed \(v \lambda\) ) has no physical
significance. Why?