a. Laser
Laser is a device which generates the coherent light or "well organised" light .Ordinary white light is made up of many different colours. Each colour has different wavelength and the photons of each colour are out of step with each other. In a beam of laser light, all the photon have the same wavelength and move in step , travelling along like a well drilled army. The mechanism relies on a process known as stimulated emission and the word laser is derived from light amplification by stimulated emission.
--The essential components of a typical laser are
1. The active medium such as a ruby rod or carbon dioxide gas
2. A method of introducing energy into the active medium, for instance a flash lamp
3. A pair of mirrors is placed on each side of the active medium, one of which transmits part of the radiation that strikes it.
A typical laser using Ruby rod as an active medium has a pulse duration of 20 nsec. with power of 10 MW and the laser beam has a wave length of 694 nm.
b. Nuclear Reactor
A device in which the fission reaction involving neutrons and nuclear fuel is controlled for the production of heat is called "nuclear reactor". It is also known as " The nuclear power plant". This heat is converted by means of turbines and generator to electrical energy for commercial use. A nuclear power plant works in a similar way to an oil-fired or a coal-fired power station. The difference between the two types of power plants is in the fuel they use to heat the boiler. Inside a nuclear power plant, energy is released by nuclear fission in the core of a piece of equipment called the reactor. The energy heats water in the boiler ( the water boils and produce steam). This steam turns the huge turbine wheels, and the turbines drive the generator that produces the electricity.
--There are three types of reactor which are given bellow.
1. Light water reactor (LWR)
2. Boiling water reactor (BWR)
3. Pressurized water reactor (PWR)
4. Heavy water reactor (HWR)
5. High-temperature Gas-Cooled reactor (HTGR)