So the bottom surface of the p-type semiconductor is mostly accumulated with positive charge carriers (holes). This produces a positive charge at bottom surface with an equal amount of negative charge at upper surface. So in p-type semiconductor, the bottom surface is positively charged and the upper surface is negatively charged. As a result, potential difference is developed between the upper and bottom surface of the p-type semiconductor. In p-type semiconductor, the electric field is primarily produced due to the positively charged holes.
T10.1b shows positive charges. In both cases the magnetic force is upward, just as the magnetic force on a conductor is the same whether the moving charges are positive or negative. In either case a moving charge is driven toward the upper edge of the strip by the magnetic force Fz = |q|vdB. If the charge carriers are electrons, an excess negative charge accumulates at the upper edge of the strip, leaving an excess positive charge at its lower edge. This accumulation continues until the resulting transverse electrostatic field E becomes large enough to cause a force (magnitude |q|E) that is equal and opposite to the magnetic force (magnitude |q|vd B).
A basic guide to resistance. Electron Flow Model Everything is made of very small particles called atoms. Each atom has a heavy positively charged nucleus and is surrounded by a cloud of light, negatively charged, electrons. In metals, the outer most electron of each atom is weakly attracted to the positive nucleus and can escape from the atom and wander around between the atoms. [Note 1] So, in metals, we have all these millions and millions of electrons whizzing about at high speed, in random directions, between the fixed atoms.
In semiconductors, the materials from which solar sells are made, the energy gap Eg is fairly small. Because of this, electrons in the valence band can easily be made to jump to the conduction band by the injection of energy, either in the form of heat or light [Book 4]. This explains why the high resistivity of semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or "lattice".
The circuit itself can resist the flow of particles if the wires are either very thin or very long. Resistance is measured in ohms. The symbol for an ohm is OMEGA. A resistor has the resistance of one ohm if a voltage of one volt is required to push a current of one amp through it. In all metals there is a sea of electrons flowing.
Electrons can move between different levels and between different materials but to do that, they require the right amount of energy and an "empty" slot in the band they enter. The metallic conductors have a lot of these slots and this is where the free electrons will head when voltage (energy) is applied. A simpler way to look at this is to think of atoms aligned in a straight line (wire). if we add an electron to the first atom of the line, that atom would have an excess of electrons so it releases an other electron which will go to the second atom and the process repeats again and again until an electron pops out from the end of the wire. We can then say that conduction of an electrical current is simply electrons moving from one empty slot to another in the atoms' outer shells.
The weight of each drop is determined by observing its rate of free fall through the air, and using Stokes' formula for the viscous drag on a slowly moving sphere. The charges thus measured are integral multiples of e. Electrons are emitted in radioactivity <as beta rays> and in many other decay processes. The electron itself is completely stable. Electrons contribute the bulk to ordinary matter; the volume of an atom is nearly all occupied by the cloud of elec trons surrounding the nucleus, which occupies only about 10^-13 of the atom's volume. The chemical properties of ordinary matter are determined by the electron cloud.
These 'free' electrons move around in the space between the atoms they are shared between the atoms in the piece of metal. The metal atom carries positive charge because they have more protons then the electrons. The positive and negative charges attract each other, so the whole arrangement is held closely together. The free electrons explain why metals are so good at conducting electricity. The movement of the electrons is what we call and electric current.
A metal wire can conduct electricity because the outer electrons of the atom are free to carry a charge. An electron is part of an atom with a negative charge and almost no mass. The more free electrons a metal has the better conductor it is. Predictions Resistance/Length I think that as the length of Nichrome wire increases so will the resistance.
At the core of every atom is a nucleus composed of protons and neutrons. Protons and neutrons are very similar in mass. The mass of these particles is measured in atomic mass units, which makes them very easy to express; protons and neutrons each have a relative mass of approximately 1 atomic mass unit. The difference between these two particles is in their charge. Protons have a relative charge of +1, while neutrons have a relative charge of 0.