Explain the lorentz - Drude theory.

Explanation

1. Drude and Lorentz, scientists of the `19^(th)` century, propsed that conductors like metal contain a large number of free electrons while the positive lons are fixed in ther locations. The arrangement of the positive ions is called lattice.
2. When the conductor is in an open circuit, the electrons move randomly in lattice space as shown in the figure.

3. If we imagine any cross section as shown above, the number of electrons, crossing the cross section from left to right in one second is equal to that of electrons passing the cross section from right to left in one second. Hence the net charge moving along a conductor through any cross section is zero.
4. When the ends of the conductor are connected to the battery through a bulb, the bulb glows because energy flow takes place from battery to the bulb.
5. This happens only due to the orderly motion.
6. When the electrons are in ordered motion, there will be a net charge crossing through any cross section of the conductor as shown in the figure.