In this tutorial we are going to learn about** **What is Resistor & Its Formula?

**RESISTOR:** Resistance
is property of resistor; It opposes the current by doing so it converts
electric energy to heat energy**
**

** R =ρl/a l – Length**

**
a – Area**

**ρ – Resistivity of material in ΩM**

**Conductor – Low Resistivity**

**Semiconductor – Medium Resistivity **

**Inductor – High Resistivity **

**Super Conductor = ρ = 0**

**Eg.
Mercury at 4.15K temp**

**Rt = R0 (1+** αt )

**R0 = Resistance of material at **0**°C**

α = Temp. Coefficient

t = Change in temp.

WHAT IS OHM’S LAW

- OHM’S LAW states that at constant temp. Current density is directly proportional to field intensity.
- At constant temp, potential difference across Element is directly proportional to current flowing through elements
- OHM’S LAW valid only when Conductivity and temp is constant .