physics ch 3 current electricity

drift velocity

the avg velocity with which each electron gets drifted towards the +ve terminal of the cell under the infulence of external electric field

mobility

the ratio of magnitude of drift velocity to electric field

Ohm's Law

the current flowing through a circuit is directly proportional to the pd across its ends provided temperature and other physical quantities remain constant

current density

J = I/A

Ohmic devices -

Devices that obey Ohm's law.

non Ohmic devices -

Devices that do not obey Ohm's law.

EMF (electromotive force)

max pd across the 2 electrodes of a cell when there is no flow of current

TPD(terminal potential difference)

pd across 2 electrodes of a cell when there id flow of current

internal resistance

is the effective opposition offered by the electrode to the flow of current through it

electrical energy

amount of energy supplied by the cell to maintain steady current

electrical power

V x I

electrical power

w/T

KCL(Kirchhoff's current law)

sum of various currents at a a junction in a a closed circuit is always zero

KVL (Kirchhoff's Voltage Law)

the algebraic Sum of changes in potential around a closed loop always equals zero.

KCl

defines law of conservation of charge

KVL

supports law of conservation of energy