How mass of an electron can be obtained ?
The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by
Define work function of metal and write its unit.
An electron gun with its collector at a potential of $100\; V$ fires out electrons in a spherical bulb containing hydrogen gas at low pressure $(\sim 10^{-2} \;mm$ of $Hg$ . A magnetic field of $2.83 \times 10^{-4}\; T$ curves the path of the electrons in a circular orbit of radius $12.0 \;cm .$ (The path can be viewed because the gas tons in the path focus the beam by attracting electrons, and emitting light by electron capture; this method is known as the 'fine beam tube' method.) Determine $e / m$ from the data.
Which is not true with respect to the cathode rays
In a Millikan's oil drop experiment the charge on an oil drop is calculated to be $6.35 \times {10^{ - 19}}C$. The number of excess electrons on the drop is