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أنجستروم Angstrom

صورة
أنجستروم  وحدة قياس للطول تساوي 10 − 10 من المتر (أي جزء من عشرة مليار من المتر). وقد سميت هذه الوحدة نسبة إلى العالم آندرز أنجستروم. أنغستروم نسبة إلى وحذات القياس الأخرى 1 أنجستروم = 0.1 نانومتر 1 أنجستروم = 0.0001 ميكرومتر 1 أنجستروم = 0.0000001 مليمتر Anders_Jonas_Ångström آندرز أنجستروم  (1814-1874) هو فيزيائي سويدي وضع أسس علم المطيافية (spectroscopy). وقد درس طيف الامتصاص الشمسي وبرهن على وجود الهيدروجين في الشمس. وحدة الطول المسماة أنجستروم والتي تساوي 10 − 10 من المتر ( أي واحد من عشرة مليار جزء من المتر) سميت بهذا الاسم نسبة إليه.
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Optics Quiz

صورة
Quiz 1. How is hyperopia corrected? a) By playing Roller Coaster Tycoon 3 for 48 hours nonstop b) With concave lenses, contact lenses, or surgery c) With convex lenses, contact lenses, or surgery d) Using hypnosis 2. When was the first lens invented? a) 100000 B.C. b) In the first century c) It’s a sad mystery d) Lenses were invented by Johann Sebastian Bach in 1727 3. What does a convex lens look like? (Click the images to view the full size image) a) b) c) d) 4. When was the first contact lens used? a) In 1887 b) In 300 B.C. c) The first lens was a contact lens, so they were invented when lenses were invented. d) In 1729 by Johann Sebastian Bach 5. What does a concave lens do to light? a) It turns it into a laser b) It concentrates the light (and it may burn you too) c) It diverges (spreads out) the light d) It bends light sideways 6. How does a concave lens correct myopia? a) By bending light inwards b) By bending light outwards c) By taking a lot of photos and sending them...
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Historical Facts

صورة
Historical Facts Lenses | Glasses | Contact Lenses | Telescopes | Microscopes Lenses As you can guess, a lens doesn’t always have to be glass. Thefirst lens was a container of water. It was discovered by the ancientRoman writer Seneca (4 B.C.-65 A.D.?). He found that images becamemagnified when seen through a glass ball filled with water. Roger Bacon (1214-1292?) invented the first convex lens in 1250. Concave lens were first used around 1450. Glasses Glasses were used in Italy around 1300. Old glasses were fastened withclips, rings, ribbons, weights, and other flexible things, or weresimply held by the hand. Temples weren’t invented yet! They had framesof tortoiseshell, ivory, metal (heavy metal), or wood. They were prettyheavy. Temples were finally invented in the 1740’s. Lorgnettes(pronounced lorn-YETS ) were also popular in the late 1700s. This word comes from the French word lorgner , meaning to leer at or stare. These were glasses held by a handle. ...
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