physical properties of metals nonmetals

Cathode rays travel in straight lines from the cathode to anode and cast shadow of the object placed in their path. (a) Cathode rays travel in straight lines. Cathode rays consist of an invisible stream of negatively charged particles. When the plates X and Y are given +ve and -ve potent..

In 1819, two French physicists Dulong and Petit discovered that the average molar specific heat at constant pressure for all metals, except the very light ones, is approximately the same and equal to nearly 25 J mole -1 o C -1 . Although the law is an approximate one, it conveys a very im..

The minimum amount of energy required to emit electrons from a metal surface is called the work function or threshold energy of that metal. The number of electrons emitted per second i.e. the rate of emission depends upon the material of the surface temperature of the surfa..

Introduction - In the chapter on current electricity, we had learnt about the flow of charges, conditions to produce the flow and how different materials respond to an external electric field. We had seen how materials are classified as conductors and insulators. In this chapter, we will study a ne..

Practical Applications of Joule's Heating - This heating is inevitable in any electrical circuit. Since the energy lost by the flowing charges ends up as disorderly thermal motion, the phrase 'ohmic dissipation' is also used to describe it. Often, this is an undesirable effect. For example, in elec..

A completely satisfactory theory of magnetism has still not been formulated. At present it is assumed that magnetism is due to the movement of the electrons. The electrons circulate around the nucleus of the atom. They also spin around an axis through their centres. These two movements set up magne..

. But, the actual result shows anomaly. This was not explained at that time. However, Planck propounded quantum theory in 1905. Einstein applied it to specific heat problem in 1907. Ultimately, Debye was successful in 1912, in fully explaining the thermal behavior of metals and non-m..

Source of Electricity - Electrons in different metals can have different energies. If two of these metals are placed in a conducting liquid (electrolyte) a difference in electrical potential is set up between them. A pair of different metals arranged in this way is an ..

A magnetic compass was used to help the sailors for navigational purpose. But recently it has been discovered that some migrant birds have magnetic sensors in their heads, which help to guide them using the Earth's magnetic field. William Gilbert suggested that Earth itself is a huge magnet from va..

The Earth's Magnetism - A magnetic compass was used to help the sailors for navigational purpose. But recently it has been discovered that some migrant birds have magnetic sensors in their heads, which help to guide them using the Earth's magnetic field. William Gilbert suggested that Earth itself ..