Resistance R = V/I V = voltage, I = current Scalar quantity Unit = ohm (Ω) Ohmeter - measures resistance
Resistance & energy loss As electric flows through a material, it heats it up The conversion from electrical potential to heat energy depends on the resistance High resistance means that a large percentage of the electrical energy is lost as heat
Ohm's Law Under constant physical conditions, the potential difference across a conductor is proportional to the current flowing through it V = IR
Combining Power, Joule's Law & Ohm's Law P = IV Joule's Law: W = I²Rt Ohm's Law: V = IR Energy output, W = VIt
Resistivity A constant associated with the resistance of a body Scalar quantity Unit = ohm metre (Ωm) Symbol = ρ
ρ = RA/l R = resistance A = cross-sectional area l = length
ρ = (Rπd²)/4l d = diameter π = mathematical constant, 3.14
New Page
Want to create your own Notes for free with GoConqr? Learn more.