Hire Writer The longer the wire is, not only do the electrons have longer to flow through the wire, there are also more collisions there would be between the electrons and the atoms.
Graphene Graphene Graphene can be defined as one atom thick layer of carbon atoms arranged in a 2- dimensional hexagonal crystal lattice.
It can be imagined as numerous benzene rings attached to each other without their hydrogen atoms being attached to them. It is the fundamental unit of other forms of carbon such as Carbon Nanotubes, graphite and fullerenes.
Carbon nanotubes can be formed by rolling the grapheme sheets in a cylindrical form. Numerous layers of graphene when stacked on top of each other forms graphite. It was established theoretically in that graphene is the fundamental unit of graphite . Since then the research of graphene has started.
The scientists and researchers had no clue about the cause of high values of conductivity displayed by graphene. Scientists researched graphene with a viewpoint of having a lighter and cheaper substitute which acts as a conductor replacing heavy metals.
The task of obtaining graphene sheets was a challenging for the researchers and hence the research work grew slowly in the late 20th century . The bond length between 2 sp2hybridized carbon atom is 0. The number of carbon atoms per unit cell of graphene is 2. The lattice of graphene can be viewed as 2 interpenetrating sub lattices.
The atoms of one sub lattice located at the center of triangles formed by the other sub lattice. The unit cell of graphene has 6-fold axis of symmetry. The p-orbitals of carbon atom lie perpendicular to the plane of graphene sheet and they hybridize to form the??
This leads to the planar conduction phenomena in graphene. The momentum of charge carriers within the Brillouin Zone determines the energy of these bands. The center of the hexagonal aromatic ring sits on top of the carbon atoms of graphene layer below it. This shows that the symmetry of the sheets is trigonal rather than being hexagonal.
Synthesis Graphite is a naturally occurring allotrope of carbon which is easily available in large quantities. We can produce grapheme sheets out of graphite both at a smaller scale for the experimental purposes as well as at large scales for the various application purposes. In the late 20th century, when the research about graphene was gaining pace, various attempts for the synthesis of graphene sheets were done.
On the same approach of producing Carbon Nanotubes, efforts were made to synthesize graphene using CVD on the metal surfaces and thermal decomposition of silicon carbide. These methods did not produce monolayer Graphene sheets but produced few stacked layers of graphene.
So CVD approach is being used widely nowadays. The approach used by the people who isolated graphene for the first time inwas peeling the graphite layer by layer.
They used the adhesive tape to peel the graphite layers one by one till graphene monolayers were produced. With this approach a very high quality graphene having micron size thickness can be produced.11E. GCSE PHYSICS INVESTIGATION.
PLAN. AIM. To find out how the length and width affect the resistance of a graphite track. INTRODUCTION.
In this experiment I will be investigating the electrical resistance of carbon in the form of graphite. My variable is the length of the graphite paper, so I will need a ruler to measure the lengths of graphite paper, a pair of scissors to cut the paper to the desired length, a pair of modified bulldog clips to attach the paper to the circuit, a power supply/battery for the electricity and some leads to link the circuit up.
The resistivity is useful for simultaneously detecting lateral and vertical changes in subsurface electrical timberdesignmag.coming to Gomiz-Ortez et al (), electrical resistivity imaging is a geophysical prospecting technique designed for the investigation of areas of complex geology; this involves measuring a series of resistivity profiles.
Again this resistivity for the 28 gauge in comparison to the resistivity for the 32 gauge is the same, where very small decimal places are slightly out. This investigation led to determining a good value for the resistivity by using two wires of different dimensions. Resistivity of wires is a factor of affecting the resistance.
Background information Electrical resistance Electrical resistance is a measure of the degree to which an object opposes the passage of an electric current.
Each time you take a measurement at a new place, rotate the wire slightly.
1 Tape the wire to the metre rule so it cannot slip and the markings of the rule are visible. .