ELECTRICITY

Ohm's Law

where,

I = current, amp

V = potential difference, volts

R = resistance, ohms

Resistivity

where,

ρ = resistivity or specific resistance, ohm-m

L = length of wire, m

A = cross-sectional area of wire, m²

Conductance (G)

where,

γ = conductivity or specific conductance, mhos/m

Electric Power

where,

P = electric power, watts

Electric Energy

where, E = electric energy, Joules

V = potential difference, Volts

I = Current, Amperes

R = resistance, ohms

t = time, seconds

E = 0.24I²Rt, cal

For Battery

where

Kirchhoff’s Law

(i) The algebraic sum of all the currents directed towards a junction point is zero.

(ii) The algebraic sum of all the voltage rise taken in a specified direction around a closed circuit is zero.

Series Circuits:

Parallel Circuits:

Coulomb’s Law

The force acting between two charged bodies q₁ and q₂ in air is proportional to the product of charges and inversely proportional to the square of the distance between them.

Posted in: FORMULAE