Resistance
- Calculate R??
- To calculate R, must calculate current which flows when voltage V is applied.
- Applying voltage V sets up an electric field in the resistor. What determines the current?
- Current is charge flowing past a point per unit time. Need to know velocity of charges. Is this determined by field?
- Field gives rise to force on charge carriers -> charge will be accelerated/scattered/accel/scat/a/s/a/s/a/s/a....
- Calculation splits here.
- Part of this we bury as the “resistivity” of the material
- Part depends on the geometry (length and cross sectional area)