What is specific charge ? Write its standard value.

Which of the following will have the least value of $\frac{q}{m}$

In an electron gun, the electrons are accelerated by the potential $V$. If e is the charge and $m$ is the mass of an electron, then the maximum velocity of these electrons will be

Kinetic energy of emitted cathode rays is dependent on

Answer the following questions:

$(a)$ guarks 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 assoctated 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?

Which of the following law is used in the Millikan's method for the determination of charge