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Resistivity and Conductivity Cheat Sheet (DRAFT) by

Bond physics

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Current

Current is the amount of net charge passing through a surface per a second.

I = q/t

I = Current (Amperes)
q = Charge (Coulombs)
t = Time (seconds)

Ohm's Law

  

Resist­ivity

Resist­ivity is a material property that quantifies how much the material restricts the flow of current.

Ohm- meter

R = p (l/a)

R = resist­ivity
p = conduc­tiity (ohms/m)
l = length
a = area of crosse­ction (m^2)
Replay

R = p (l/a)

What happens if the area is larger?
the smaller the resistence
What happens if you increase the length?
the larger the resistence
 

Power

Work per unit time.

P = IV = I2R = (v)2/R

Original formula is P = IV. With this formula, apply Ohm's law and the rest will follow.

Power = energy * time

Power (Watts)
Energy (kWhr,
Time (seconds)

energy = (power) (time)

Energy (kWhr, Joules)
Power (Watts)
Time (seconds)