Light - online puzzles

Light

Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization. Its speed in vacuum, 299792458 m/s, is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and particles. The study of light, known as optics, is an important research area in modern physics.

The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.

Picture 1 puzzle online from photoOld telephones online puzzleChristmas London puzzle online from photoballoons online puzzleToy car puzzle online from photoRome puzzle online from photoNature Gallery online puzzleWinter... puzzle online from photodishes online puzzleAlchemia Gdańsk puzzle online from photoPassage puzzle online from photoHamburg puzzle online from photoJewellery puzzle online from photoWarsaw online puzzleFlores puzzle online from photoWater Gate in Grudziadz at night puzzle online from photoBoston, Massachusetts, USA downtown skyline puzzle online from photoAmsterdam puzzle online from photoeggs 2 puzzle online from photoCharming nooks by the water online puzzleSitges online puzzleMercedes AMG GTR online puzzleTHE WORLD OF OLD WARSAW online puzzleTraffic... puzzle online from photo
jewellery online puzzlerings puzzle online from photoWinter menu puzzle online from photoLondon collage online puzzleLos Angeles online puzzleColorful Mosaic online puzzleTraffic... online puzzleWindmills puzzle online from photojeep willys puzzle online from photoCollage-Moscow puzzle online from photoCagliari puzzle online from photoBeverly Hills puzzle online from photoHollywood online puzzleLondon collage puzzle online from photoBatllo's cash register puzzle online from photoFLORENCE puzzle online from photoHighlander inn online puzzleBogdaj-church interior online puzzleChristmas London online puzzleCollage puzzle online from photoFlorence-collage puzzle online from photoSardinia puzzle online from photoCar puzzle online from photoCagliari puzzle online from photo