Knowledge N Fact4u

Why doesn't   a   laptop emit radiation ? •Your laptop computer does emit radiation. In fact, your laptop emits several different kinds of radiation: •400 to 800 THz electromagnetic radiation. This is the visible light given off by the laptop's screen that makes it possible for you to see what the computer is displaying. Yes, ordinary visible light is a form of radiation. •10 to 100 THz electromagnetic radiation. This is the infrared radiation given off by all parts of the laptop due to their temperature, through the everyday process of thermal emission. •5 GHz or 2.4 GHz electromagnetic radiation. These are the radio waves given off by the WIFI antenna in the laptop, which are used to connect to a wireless network. •2.4 GHz electromagnetic radiation. These are the radio waves given off by the Bluetooth antenna in the laptop, which are used to connect wirelessly to peripheral devices such as a cordless mouse. •Low frequency electromagnetic radiation. These...

How do tractor beams work ? •Up until recently, tractor beams (beams of light that tow objects) existed only in the world of science fiction. •While large-scale tractor beams that can tow space ships are still machines of the future, microscopic tractor beams are here today.  •The idea at first seams to defy physics. Shoot light at an object and the light's momentum should push the object away from the light source according to the law of conservation of momentum; not pull it closer like a tractor dragging its cargo. •But what if you managed to create a situation where upon striking the object, the light gains forward momentum instead of losing it.  •In that case, the law of conservation of momentum tells us that the object will lose momentum in the forward direction, even to the point of going backwards, towards the light source. •So there is a way to make a tractor beam without violating any physics, if you can get the light to ga...

Used increasingly in digital products, how does this technology work? Electronic ink (or electrophoretic ink) consists of millions of microcapsules. Each one contains positively charged white particles and negatively charged black particles, all suspended within a clear fluid. When these microcapsules are subjected to a positive or negative electric field, the corresponding particles rise to the top, becoming visible to the eye and colouring that microcapsule.  eBook reader displays coat electronic ink onto a sheet of plastic film, which in turn is laminated to a layer of circuitry. This circuitry forms a pattern of pixels that can be controlled by the display’s software driver, allowing images and text to be displayed in the form of a traditional page of physical paper.   Electronic ink displays differ from LCDs by utilising ambient light to illuminate pixels, with the rays merely reflecting off their surface. This means they have very low power demand, a...

Why do diamonds last forever ? •Diamonds do not last forever. Diamonds degrade to graphite, because graphite is a lower-energy configuration under typical conditions. •Diamond (the stuff in wedding rings) and graphite (the stuff in pencils) are both crystalline forms of pure carbon. •The only difference is the way the carbon atoms are arranged and bonded in the crystalline lattice. •In diamond, each carbon atom is bonded to four neighboring carbon atoms in a closely-packed three-dimensional grid. •In graphite, each carbon atom is strongly bonded to three neighboring carbon atoms in a plane and the planes of atoms are loosely bonded to each other. •The degradation of diamond to graphite is a simple case of the atoms internally rearranging and relaxing to a lower energy state. This process requires no chemical reaction with an external material. •Although graphite is a more stable form of crystalline carbon than diamond under normal conditions, there is a significant kinetic ...