Wireless Charging of devices

Now a days, we heard of wireless charging of mobiles through power mats. The basic concept of wireless charging is in faraday's law, the law states that whenever a conductor is placed in time changing electric field an emf(Electro motive force) called as voltage is induced in that particular conductor. This concept is used and is applied to wireless charging of devices.

Whenever a mobile is placed in power mats, this power mats are capable of emitting alternating current which will create a magnetic field and mobile is equipped with conductor(wireless charging contacts), and now according to the law, this magnetic field will induce the voltage in the conductor and the mobile gets charged

.

Only power mat need to be plugged in. With this concept, with one plug and one cord we can charge many devices by placing on power mat.

Read more ...

SUPER CONDUCTORS-EXPLAINED

        Now we will learn about new concept called 'SuperConductors'.We will start from beginning,metals are classified into 3 types conductors,semiconductors and insulators.when voltage is applied to conductors or semiconductors,electron flow(current) occurs, and this flow is restricted by resistance which is the property of conductors.This resistance is resulted due to impurities,defects and vibrations of materials in the crystal lattice.This phenomena is called resistivity which depends upon length and area of the conductor.

        Inverse of resistivity is conductivity.conductivity of conductor lot depends on temperature.Normal conductors conduct below 30k.Scientists worked a lot to increase the conductivity of a conductor.They have varied the temperature but couldn't get much from conductors,because the conductors already have free electrons and increase in temperature will further add energy to this free electrons which makes them to move in less organised patterns making less conductivity at higher temperature.This is not the case with semiconductors,when temperature is increased,the energy is added and in turn helps to free a electron,so at high temperatures more electrons are freed which increases the conductivity.This kind of transition from normal conductivity to super conductivity which will occur when we go from room temperature to high temperature is called Superconducting state and the metals are called Super conductors.The phenomena of exactly zero electrical resistance occurring in certain metals when they are at high temperature is called Superconductivity.

What causes superconductivity?
        We had seen that certain metals suddenly become superconductors,when they are kept at critically high temperature.Reason is, at this temperature electrons inside them will join with each other which are called copper pairs.At this temperature electrons will move more freely without being scattered.High temperature will result more free electrons thus increasing the conductivity of semiconductors at high temperature.At present scientists are working hard to have this feature at room temperature.

        Another interesting thing that need to pay attention with superconductors is Meissner Effect.Normally materials allow magnetic fields to flow through them,but when semiconductors were at high temperature,they increasingly expel these fields.This effect is called Meissner effect and the principle is used in maglev trains.

        Technological applications of superconductors are adopted in Maglev trains,MRI(Magnetic Resonance Imaging) and NMR(Nuclear Magnetic Resonance) as they require strong electromagnetic fields. 

Read more ...