In 1830 Michael Faraday predicted a relationship between the charge passed and the amount of a substance oxidized or reduced at an electrode. His proposal was based on two main arguments related to electrolytic processes:
i) The amount of chemical change produced by an electrical current is proportional to the quantity of electricity passed. ii) The amounts of various substances liberated by a given quantity of electricity are inversely proportional to their chemical equivalent weights.
These principles are come to life mathematically as follows:
W = ItA / nF (1.3) where, W - weight of the substance,
A - Atomic or molecular weight,
I - Current,
F - Faraday’s constant, n - Number of valence electrons participating in the reaction, t - Time elapsed.
Thus the electrodeposition is the simplest of the chemical methods, and it has many advantages (Chopra 1969) like
Structurally and compositionally modulated alloys and compounds can be deposited which are not possible with other deposition techniques.
In most of the cases the deposition can be carried out at room temperature enabling to form the semiconductor junctions without inter diffusion. Deposition on complex shapes is possible.
Toxic gaseous precursors need not to be used (unlike gas phase methods). The deposition process can be controlled more accurately and easily
Factors governing electrodeposition
The preparatory parameters directly affect the structural and morphological properties of the electrodeposits. The various preparation parameters like substrate, bath temperature, complexant, applied field and current density, and pH of the bath etc. should be controlled to obtain uniform and smooth deposits (Gaikw...
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...in film research originated from space and defence programmes to which the device cost is less important than its lightweight. The major applications of thin film technology are not now exclusively in these areas but rather often lie in the domestic sector in which low cost is essential (Chopra 1969, West 2003). Thin film materials have already been used in semiconductor devices, integrated circuits, telecommunications, wireless communications, rectifiers, transistors, solar cells, flat-panel displays, photoconductors, light-emitting diodes, light crystal displays, magneto-optic memories, audio and video systems, compact discs, electro-optic coatings, memories, multilayer capacitors, smart windows, computer chips, magneto optic discs, lithography, micro electromechanical systems (MEMS), and multifunctional emerging coatings and other emerging cutting technologies.
Electricity is an interesting subject. There is so much you can learn from it, like how our lights turn on or how we make cell phones. This is all a mystery until we finally get a little bit of information in our brains. I've just read two articles, "Energy Story" and "Conducting solutions". I also watched a video called Hands-on Science with Squishy circuits. I learned so much valuable information from these resources.
Therefore any changes in the cell are ascribable to the working electrode. The control of potential of working electrode with respect to reference electrode is equivalent of the controlling of energy of electrons within the working electrode. As shown in Fig. 1.3, scanning the potential in the negative direction makes the electrode a stronger reductant, whereas scanning the potential in the positive direction makes it a better
was first conceived by Michael Faraday in the year 1832 in his Backerian Lecture to
One thunderous afternoon on June 1752, Benjamin Franklin conducted what is known today as the “Kite Experiment”. He wanted to prove that if one object was electrical, the energy from that object could be transferred to another object, therefore being classified as electricity and lightning. With his son William, Ben took a string and attached the kite to it, then he attached an iron key to the kite. Next, they tied a thin metal wire from the key and put the wire inside a Leyden jar which stored all the electrical charge. His experiment profitably showed that his accusations were correct. Many other scientist tried the same experiment and were electrocuted, but Ben Franklin was the lucky one. He changed the world of science.
Thin films are thin material layers ranging from fractions of a nanometer to several micrometers in thickness.
Benjamin Franklin developed a theory that every object had an "electrical fluid". He believed that some objects had too much of this fluid, while others did not. By putting his theories together, he invented the electrical battery. It was made out...
When introduced into an ionic solution, positively charged ions will be electrostatically attracted to the anode and the negatively charged ions will be electrostatically attracted to the cathode. This act of moving ions means that charges are able to move from anode to the cathode and complete the circuit. These moving ions are essentially the same as moving electrons (electricity). This process of putting electrodes into a solution, using a direct electric current (D.C.), and separating chemicals based on their charge is known as electrolysis
Michael Faraday was the man behind the discovery of electromagnetic induction. Electromagnetic induction is the creation of an electric current by using a magnetic field. Faraday’s first experiment was set up by coiling to separate lengths of copper wire around a wooden block. The two coils had to be separated he did this with thread. One of the coils was connected to a galvanometer (an instrument used to detect small electrical currents), while the second coil was connected to a battery and switch. As Faraday closed the switch there was a small and brief change in the reading on the galvanometer. What this meant was that Faraday had seen a little and concise current that passed through the galvanometer circuit. Faraday observed the same affect in the galvanometer circuit when the battery circuit was turned off, except the change was in the opposite direction or negative of the first reading of the galvanometer.
It is highly beneficial to be able to calculate the concentration of a saturated solution. Indeed, knowledge of the concentration is required to calculate solute solubility and if precipitates will form when the solution is mixed with other reagents. This has many applications in industrial processes. For these reasons, this experiments aims to determine the concentration of a saturated barium hydroxide (Ba(OH)2) solution by conductometric titration and gravimetric analysis. Conductometric titration involve examining the change in Ba(OH)2 (aq) conductivity as sulphuric acid is added. Conductivity initially has a high reading due to the presence of ions in solution and then reaches a minimum at the reaction endpoint, due to complete neutralisation
In some Greek experiments, objects attracted each other after rubbing. Other experiments produced objects that pushed away, or repelled, each other. The evidence showed that electric force made matter either attract or repel other matter.
First off, what is current. Current is expressed in a unit called Amps. Amps are a measurement of how many electrons pass per second. That is to say, a wire with 40 coulombs passing any point in a 2 seconds would be said to have 20 Amps of current (40 Coulombs (a unit of charge given as 6.24x1018 electrons) / time in seconds or in this case, 2 seconds. The Amp is also known as Coulombs per second) Another trick about current is that it is measured in the movement of the positive charge. Literally that is to say the current moves in oppostion to the electrons. This is because originally it was thought that the positive charge is what moved, both are viable, but in reality a positive charge is generally fixed since within an atom the electrons are migratory, while the protons and neutrons tend to be stationary.
Chemicals involve in this battery are porous lead as the anode, lead(IV) oxide as the cathode and sulfuric acid as the electrolyte.
Electrophoresis is an analytical technique for the analysis of macromolecules like proteins and nucleic acids. This technique was discovered and first used in 1937 by a Swedish biochemist Arne Tiselius . The electrophoretic effect is based on the theory of Debye - Huckel - Onsager where this theory of electrolytic dissociation accept the fact that charged particles move up under the influence of electrostatic forces to an electrode of opposite charge is applied when a potential difference in a solution containing electrolytes.
The history of engineering goes back into the 19th century when Alexander Volta (1745-1827) made a remarkable discover regarding the nature of electricity (Cosgrove 749). He discovered that electrical current could be controlled and could flow from one point to another. By the time the mid-19th century came about the rules for electricity were being established. During this time electromagnetic induction was discovered by Michael Faraday who lived from 1791 to 1867 (749). Also during this time Samuel Morris invented the telegraph in 1837 which relies on the principles of electromagnetic induction (749). Alexander Graham Bell, who lived from 1847 to 1922, created the telephone which also uses electricity in order to operate (749). Through the success of the telephone, Bell Telephone Company was established. In 1878, the light bulb was finally invented by Thomas Edison who lived from 1847 to 1931 (749). Off the principles of Faraday’s electric motor from 1821, Nicholas Tesla invented a more efficient and powerful electric motor in 1888 (749). To make these inventions be more significant, effort was expended to make better motors and transformers and to enhance the power needed to make them function. Through these inventions during the middle 19th century, it led to the capability of lighting homes and cities through the use of electricity, and it also led to the creation of the telephone communication system (750).
Faraday continued his electrical experiments. In 1832, he proved that the electricity induced from a magnet, voltaic electricity produced by a battery, and static electricity was all the same. He also did significant work in electrochemistry, stating the First and Second Laws of Electrolysis. This laid the basis for electrochemistry, another great modern industry.