Question

What is the effect of an increase in temperature on resistance?

Answer 1

Resistance:

1. Resistance is known as the measure of the opposition to current flow in an electrical circuit.
2. Mathematically, Resistance $\left(R\right)$ = $\raisebox{1ex}{$V$}\!\left/ \!\raisebox{-1ex}{$I$}\right.$, Where $V$=Voltage and $I$= current.
3. Resistance is measured in ohms, Its symbol is the Greek letter omega $\left(\Omega \right)$.
4. Ohm is named after Georg Simon Ohm, a German physicist who studied the relationship between voltage, current, and resistance.

Heating effect on resistance:

Mathematically, $R=R_{ref}\left[1+\alpha \left(T-T_{ref}\right)\right]$ Where $R$ = resistance, $R_{ref}$= resistance at the reference temperature,

$\alpha$=temprature coefficient of resistance for conductor material. $T$=conductor temperature in degree celsius, $T_{ref}$ = Reference temperature.

1. Resistance is dependent on the length of the conductor, material area, and the type of material of the conductor.
2. Resistance is inversely proportional to conductivity as evident from the above formula.
3. Heating the metal conductor causes atoms to vibrate more as their kinetic energy increases while heating.
4. As electrons move through a metal conductor, some collide with atoms, other electrons or impurities.
5. This makes it more difficult for the electrons to flow, increasing resistance.

Thus, on heating a conductor, its resistance increases.