Tuesday, January 15, 2008

Something to learn from the basic

Today I learnt something that ius not new to most science student, a study done a group of researchers from Central Education Institute of KEPCO in Seoul, South Korea.

Something to do with Ohm's Law
Ohm's Law states that
"For any particular conductor at a constant temperature, the current that flows through it is directly proportional to the potential difference applied across it."
Resistance is a property of a particular conductor and depends on:
The material of which the conductor is made.
The length, L, of the conductor (R µL).
The cross-sectional area, A, of the conductor (R µ A-1)
The temperature of the conductor. (Resistance increases non-linearly with temperature).

Resistance
An electron traveling through the wires and loads of the external circuit encounters resistance. Resistance is the hindrance to the flow of charge. For an electron, the journey from terminal to terminal is not a direct route. Rather, it is a zigzag path which results from countless collisions with fixed atoms within the conducting material. The electrons encounter resistance - a hindrance to their movement. While the electric potential difference established between the two terminals encourages the movement of charge, it is resistance which discourages it. The rate at which charge flows from terminal to terminal is the result of the combined affect of these two quantities



Resistance = rho ( length)/Area
resistivity