Electric Fields & Capacitance

Coulomb

A charge of 1 coulomb passing a point when a current of 1A flows for 1 second

Electric Field

Region of space where a force per unit charge acts on a particle with charge

Electric Field Lines

Lines representing field strength, arrows show direction of force on a positive charge

Electronvolt

1 eV = 1.6x10^-19 J

Coulombs Law

Electric force is proportional to the product of the charges and inversely proportional to their seperation squared

Electric Field Strength

Electric force per unit positive test charge

Electric Potential

Work done per unit charge in bringing a small positive test charge from infinity to a point in a electric field

Electric potential energy

Work done by an external force in bringing a small positive test charge from infinity to a point in a electric field

Potential Gradient

Electric field is the negative gradeint of electric potential

Capacitance

Charge per unit potential difference across the plates

Exponential Decrease/Decay

A graph where rate of decrease is proportional to the quantity itself

Time Constant

The time taken for the charge on a capacitor to decrease to 37% of its original value, product of R and C