jobyts said:What causes electric resistance for a material (in terms of molecular or atomic level)?
Also, it should be possible to derive the resistance of a material by it's atomic/molecular properties theoretically, right? (without using voltage and current).
ZapperZ said:In most material, at ordinary temperatures, it is due to the electron-phonon scattering. What this means is that the vibration of the lattice of the material collides with the movie electrons (or holes). This is why the resistivity increases as the temperature goes up. The higher the temperature, the more the lattice vibrates, the more frequent the electrons/charge carriers scatter.
Zz.
Electric resistance is the measure of an object's opposition to the flow of electric current. It is caused by the collisions of electrons with atoms in a material, which generates heat and decreases the flow of current.
The factors that affect electric resistance include the material of the object, its length, cross-sectional area, and temperature. Materials with high resistance, longer lengths, and smaller cross-sectional areas tend to have higher resistance, while temperature can either increase or decrease resistance depending on the material.
Electric resistance is measured in ohms (Ω) using an ohmmeter, which passes a small electric current through the object and measures the voltage drop. The resistance is then calculated using Ohm's law (R=V/I), where V is the voltage and I is the current.
Understanding electric resistance is crucial in designing and maintaining electrical circuits. It helps in selecting the appropriate materials, sizes, and lengths of wires and other components to ensure efficient and safe flow of current. It is also important in fields such as electronics, telecommunications, and power generation.
Electric resistance can be reduced by using materials with lower resistance, shorter lengths, and larger cross-sectional areas. Additionally, keeping the temperature of the material low can also decrease resistance. In some cases, adding a conducting material, such as copper, can also help reduce resistance.