Light is the form of radiant energy which, by its effect upon the retina, excites the sensation of vision. There are many reasons for supposing that this action is a vibration of the ether. This vibration, unlike sound vibration, is transverse, - that is, perpendicular to the direction in which the light is moving.

Luminous bodies are those that emit light. The term is usually applied to those bodies only that are self-luminous. When light falls upon a body, part of it is reflected; part is absorbed by the body, changing the molecular or atomic force; and part may or may not pass through the body. Transparent bodies are those that permit light to pass through them in such a way that objects are distinctly visible through them. When light comes through a body as diffused light, and objects cannot be distinctly seen through it, the body is called translucent. If the body does not permit light to pass through at all, it is called an opaque body.

The classification of bodies as opaque and transparent is not very accurate, for thick layers of transparent bodies absorb a great deal of light, while thin layers of opaque substances are sometimes transparent.

Demonstration. - The transparency of gold leaf can readily be shown by laying a piece of gold leaf upon a glass plate and covering it with another plate of the same size. It is well to bind these together with a strip of gummed paper such as is used in making lantern slides. Hold the plates close to the eye and objects can be seen clearly through the gold leaf. Compare the color of the transmitted light with the color that is reflected from gold. 

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم الشؤون الطبية يقدم الخدمات الصحية والعلاجية لزائري مدينة سامراء

العتبة العباسية المقدسة تقدم خدماتها لزائري مرقد الإمامين العسكريين (عليهما السلام) في سامراء

المجمَع العلمي ووفد وزارة التربية يبحثان سبل التعاون المشترك

قسم الشؤون الفكرية يصدر العدد 192 من مجلة الرياحين للأطفال

المزيد

الآخبار الصحية

كنز غذائي على طبقك.. ماذا تفعل السبانخ بجسمك؟

ما لا يتوقعه أحد.. "سر غذائي" في الجبن الدسم

لتحسين الهضم والنوم.. هذا أفضل وقت لتناول العشاء

10 طرق بسيطة وغير مألوفة لحرق المزيد من السعرات يوميا

المزيد

الآخبار التكنلوجية

سابقة بعالم الطيران.. طائرة تقرر الهبوط بنفسها بعد ظرف طارئ

"الإنفلونزا الخارقة" تكتسح دول العالم.. وتثير قلقا كبيرا

مرحلة ما قبل الأعراض.. دواء جديد يستهدف "شرارة" الزهايمر

إزالة ثاني أكسيد الكربون من الغلاف الجوي.. ما دور المحيطات والبحار؟

المزيد

مواضيع ذات صلة

Angles of Incidence and Refraction

Diffraction

The Laws of Refraction

Polarized Light

Indices of Refraction

The Propagation of Light

Spherical Aberration

Double Refraction

الضوء

The Color of Transparent Bodies

The Color of Opaque Bodies

The Secondary Bow