#12.1.1
Cathode rays
Production of cathode rays in a discharge tube.
#12.1.2
Thermionic emission of electrons
The principle of thermionic emission.
Work done on an electron accelerated through a pd V;
\(\dfrac{1}{2}mv^2 = eV \)
#12.1.3
Specific charge of the electron
Determination of the specific charge of an electron, \(\dfrac{e}{m_e}\), by any one method.
Significance of Thomson’s determination of \(\dfrac{e}{m_e}\)
Comparison with the specific charge of the hydrogen ion.
#12.1.4
Principle of Millikan’s determination of the electronic charge, e
Condition for holding a charged oil droplet, of charge Q, stationary between oppositely charged parallel plates.
\(\dfrac{QV}{d} = mg \)
Motion of a falling oil droplet with and without an electric field; terminal speed to determine the mass and the charge of the droplet.
Stokes’ Law for the viscous force on an oil droplet used to calculate the droplet radius.
\(F = 6πηrv \)
Significance of Millikan’s results.
Quantisation of electric charge.