Key Terms
Units
Joules (J), with Q in coulombs, V in volts, C in farads.
Used for
Submicroscopic processes - atomic, molecular, nuclear energies.
Units check
V/m = N/C (both valid units for electric field strength)
Positive charge
V is positive, decreases with distance. Negative charge: V is negative, magnitude decreases with distance.
Equipotential line
A line (or surface in 3D) along which electric potential is constant.
Grounding
Connecting a conductor to Earth with a good conductor, fixing it at 0 V.
Capacitor
A device that stores electric charge.
Typical capacitors
Picofarads (pF) to millifarads (mF). One farad is enormous.
Physical intuition
More area lets charges spread out; closer separation strengthens attraction between opposite charges.
Dielectric
An insulating material placed between capacitor plates.
WHY DIELECTRICS WORK
Polarization. The insulator's molecules align with the field; their slightly separated charges attract more charge onto
Dielectric strength
The maximum E field before the material breaks down and conducts. Exceeding it means sparks; capacitor fails.
Rule
Same voltage V across each capacitor. Charges add.
Result
C_total is greater than any individual capacitor.
Physical reason
Parallel connection increases effective plate area; larger A = larger C.