1. Telescope (1608):
-An optical instrument which allows us to observe and study distant objects in the universe like stars,planets,galaxies and other celestial bodies.
-A Dutch spectacle maker Hans Lippershey in 1608 discoverd the first practical Telescope.
-However,in 1609 an Italian astronomer Galileo Galilei improved his design and created a more powerful and accurate Telescope.
-Over the years, many significant changes has been done to increase it's effectiveness and reliability.
-It is used for Astronomical research, exploration of the space by scientists,for studying the Earth's atmosphere which improves weather forecasting,for inspiration of people about astronomy and universe.
-It works on the following principles:
•Light collection:It collects light from a distant object like stars or planet.
• Focus and magnification: The light collected is focused and magnified by the telescopes optics thus creating an image.
•Observation and Analysis:The image formed is then observed and analyzed by astronomers to break down the object's composition,temperature and motion.
-There are four types of telescopes:
•Refracting Telescope
•Reflecting Telescope
•Radio Telescope
•Space-based Telescope
2. Microscope (1590):
-An optical instrument which allows us to study and observe tiny objects,structures or organisms which are named to the human eye.
-Dutch spectacle maker Zacharias Janssen discoverd first compound microscope in 1590.
-Over decades and centuries,microscope has undergone significant changes like development of achromatic lenses,phase contrast microscopy,fluorescent microscopy,super resolution microscopy and scanning probe microscopy.
-They have been proved to be an essential tool for biological research,medical diagnosis,material science and quality control.
-It works on the following principles:
•Specimen preparing: A specimen is prepared and placed on the microscope as slide.
•Illumination:Slide is illuminated by light which is then observed by microscopic optics.
•Magnification:Slide is magnified which is then observed through the microscopic lens(eyepiece).
•Image Analysis:Image observed is analyzed and interpreted for its composition and behavior.
-It is of four types:
•Optical Microscope
•Electron Microscope
•Fluorescence Microscope
•Confocal Microscope
3. Laser (1960):
-The word laser stands for Light Amplification by Stimulated Emission of Radiation.
-It is a device which produces a concentrated beam of light by amplifying light through stimulated emissions.
-It's concept was proposed by Albert Einstein in 1917 when he described the process of stimulated emissions.
- The first walking laser was developed in 1960 by Theodore Maiman using a synthetic ruby rod.
-Over the years, it has been significantly changed including development of semiconductor lasers,fibre lasers and ultra short pulse lasers.
-It is used in medicine for surgical procedures like cancer treatment,eye surgery,also used in industry for cutting and welding, used to transmit data through fibre optic networks.
-It works on the following principles:
•Stimulated Emission: An excited atom releases a photon which then stimulates other atoms to release photon.
•Gain Medium:A crystal or gas(gain medium) is excited by an energy source thus producing population inversion.
•Optical Cavity:The gain medium is placed in an optical cavity,which provides feedback and amplifies the light.
•Output beam: The amplified light is emitted as a concentrated beam,which can be directed and focused.
-There are four types of lasers:
•Gas lasers
•Solid-state Lasers
•Fiber Lasers
•Semiconductor lasers
QUANTUM MECHANICS AND NUCLEAR PHYSICS
1. Transistor (1947):
-It is a semiconductor device which amplifies or switches electrical signals.
-It was Invented in 1947 by John Bardeen,Walter Brattain and William Shockley at Bell Labs.
-However in 1951 using a germanium-based material first practical transistor was developed.
-Over the years,it has undergone significant changes including bipolar junction transistors(BJTs) ,Field-effect transistors (FETs) and metal-oxide semiconductor field effect transistors(MOSEFTs).
-It is used as an amplifier in television,radios, also used in switches like digital circuits,used as voltage regulators which helps in management of power,also used in communication systems such as telephones and satellite systems.
-It works on the following principles:
•Semiconductor material: Silicon,a semiconductor material is used to control the flow of electric current.
•Base,collector and Emitter:these are three layers of transistors.
•Amplification and Switching:Whenever a voltage is applied to the base,it amplifies or switches the current flowing between the collector and Emitter.
-These are of three types:
•Bipolar Junction transistors(BJTs).
•Field-effect transistors(FETs).
•Metal-oxide semiconductor field effect transistors(MOSFETs).
2. Scanning Tunneling Microscope (1981):
-It is a powerful tool which allows us to visualize and manipulate individual atoms on surfaces.
-Gerd Bining and Heinrich Rohrer were awarded with Nobel Prize in Physics in 1985 for their pioneering work in invention of STM.
-It is used in nanotechnology to study structures on nanoscale,used in biological research to study proteins and DNA,used in surface physics to study phase transitions and reactions.
-It works on the following principles:
•Tunneling Effect:In this, the electrons can pass through a barrier allowing us to feel surface of materials.
•Probe tip: A sharp tip is brought close to the surface of the material where a voltage is applied between tip and surface.
•Tunneling current:Then the current flowing between tip and surface is measured which provides information about surface topography.
•Scanning:Lastly,probe tip is scanned across the surface which creates a three dimensional image of the surface atoms.
-It's key features are as follows:
•Atomic Resolution:It's resolution ability allows us to visualize individual atoms on surfaces.
•Real-time Imaging:It can create images in real time which enables us to study dynamic process and surface reactions.
•Manipulation:It can be used to manipulate individual atoms on surfaces which allows us to create structures on nanoscale and study their properties.
3. Nuclear Reactor (1942):
-A device which uses nuclear fission to generate heat,which is then used to produce steam and drive a turbine for generation of electricity.
-It was Developed by Enrico Fermi and his team in 1942 and contributed in providing a significant portion of electricity to the world.
-It used for electricity generation,propulsion,space exploration,research and development.
-It works on the following principles:
•Nuclear Fission:A process in which atomic nuclei split to release energy.
•Fuel:A fuel is typically uranium which undergoes fission to release heat.
•Moderator: Water or graphite being moderator slows down the neutrons released by the fission process to increase the rate of reaction.
•Control Rods:These are made of neutrons absorbing material which regulates the rate if reaction by absorbing the excess of neutrons.
-It has some safety features like:
•Containment structure
•Coolinh systems
•Emergency cooling core system
•Radiation Monitoring
-It is of four types:
•Pressurized water Reactor(PWR).
•Boiling water Reactor(BWR).
•Gas cooled Reactor
•Liquid metal fast breeder Reactor (LMFBR).