Explain liquid drop model of atomic nucleus.

Explain liquid drop model of atomic nucleus.
Explanation-
According to this model a necleus can be assumed to be like a liquid drop for the following reasons-
(i) The stable necleus is spherical in shape due to symmetrical surface tension forces.
(ii) Such as the surface tension forces act on thevsurface of the liquid-drop similarly a potential barrier to surface of the nucleus acts.
(iii) The nuclear force are short range forces. Similarly, in liquid drop, the intermolecular forces are short range forces.
(iv) The density of liquid drop is independent of its volume. Similarly the density of nucleus is independent of its volume.
(v) On rising the temprature of liquid the molecules evaporate. Similarly, when energy is given to the neucleus a compound nucleus is formed which emits nucleons almost immediately . 

History of superconductivity

Superconductivity is a state exhibited by many conductors when cooled below their superconductivity transition temperature. Superconductivity is one of the most fascinating physical phenomena having a vast potentiality in practical application. A superconductor material exhibits zero electrical resistivity and complete diamagnetism. The superconducting state is influenced by temperature, magnetic field, and current. There exist critical values for these three parameters, above which values the material passes into normal state.   

What is a LASER ?

The word LASER is the short of light amplification by stimulated emission of radiation. Laser is that device is which an intense, monochromatic, coherent and uni-directional light beam is obtained. It was discovered in 1950, by Townes and Shallow.
Thus, a Laser produces a light beam in which all the waves are of same frequency.  all waves are in same phase and all waves travel in a definite direction

What is Newton's Rings

When a Plano-convex lens with its convex surface is placed on a plane glass plate, an air film gradually increasing thickness is formed between the two. The thickness of the film at the point of contact is zero. If monochromatic light is allowed to fall normally, and the film is viewed in reflected light , alternate dark and bright concentric rings with their center dark is formed between the lens and glass plate are seen. Since the phenomenon was described by Newton that is way the rings are known as Newton's Rings after his name.

Explain the Interference of Light.

When two light waves superimpose, then the resultant amplitude ( or intensity ) in the region of superposition is different then the amplitude of individual waves. this modification in distribution of intensity in the region of superposition is called inerteference. 
When the resultant amplitude is the sum of the amplitudes due to two waves, the interference is known as constructive interference and when the resultant amplitude is equal to the difference of two amplitude, the interference is known as destructive interference.


Types of interference-
i) Division of Wavefront
ii)Division of Amplitude

What is core type transformer ?

Constructionally there are rwo types of transformers i.e. Core type transformer and Shell type transformer. There are differ from each other by the manner in which the winding are wound around the magnetic core.
Core type transformer- in Core type transformers , the windings surround a considerable part of the core, i.e. The half turns of primary and secondary windings are placed on each limb (core).
Generally, circular coils are used in core transformer because of their mechanical strengh. Such cylindrical coil are wound in helical layer with the different layers insulated from each other by paper, cloth, micarta board or cooling ducts. Figure shows the diagram of Core type transformer.

What is Compton Effect?

In 1921, Professor A.H. Compton discovered that whrn a mono-chrometic beam of light of high frequency radiation ( X-rays, Y-rays, etc.) is scattered by a substance, the scattered radiation contain two components
-One having a lower frequency or greater wavelength and the another having the same frequency or wavelength.
The radiation of of unchanged frequency in the scattered beam is knows as unmodified radiation while the radiation of lower frequency is called as modified radiation.
And the difference in wavelength is known as Compton Effect.