Phenomenon of superconductivity was first observed by Kamerlingh Onnes in Leiden in 1911 ,3 years after he first liquified helium gas. He observed that electrical resistivity of such as mercury, tin, lead completely disappear i.e., suddenly dropped to zero in a small range of temperature at a critical temperature TC which is the characterstics of the material.
We already know about gravitational and electrostatic forces now a question arises that does these forces still hold when we talk about nuclear dimensions as gravitational force between two protons is far too less to hold them and electrostatic force between two protons always a force repulsive in nature . So what hold protons together to form a nucleus.
1. X-Rays are emitted from metal when metal surface is hit by high energy electrons. The electrons penetrate close to the nucleus and displace electrons around the nucleus. The enerfy change is equal to hf where f is the frequency and is very high for radiation emitted.
2. X-Rays are EM waves of very high frequency and short wavelength near about a 100 times shorter then the wavelength of visible light.
Nuclear fission is said to have occurred when nucleus of an atom splits into several small fragments. In nuclear physics nuclear fission either occurs as a nuclear reaction or as a radioactive decay process in which nucleus of an atom splits into smaller and lighter nuclei. The fission process often produces free neutrons and photons (in the form of gamma rays), and releases a very large amount of energy even by the energetic standards of radioactive decay.
Many materials like carbon can exist in various forms for example it can exist as diamond in solid form and graphite is also one form of carbon and clearly dimond and graphite have different mechanical, thermal, optical and electrical properties. These properties of different forms of carbon can be understood in terms of carbon atoms in the solid structure.