---> It is a proportionality in ohm's law relating current to potential difference.
---> Opposition to the flow of current and in doing so converts electrical energy in to heat energy.
V=RI
I=V/R=G
Where GV= 1/R, R and G are respectively resistance and conductance of a conductor.
---> resistance depends on physical condition of conductor, mainly on the temperature.
---> If conductor positive temperature co-efficient then resistance of conductor increases with temperature revers happens for negative temperature co-efficient.
---> resistance are connected in series current through all resistance are same but voltage across them are different.
R=R1+R2+R3+R4.........+Rn
---> Resistor are connected in parallel current through each resistance are different but voltage across them are same.
1/R=1/R1+1/R2+1/R3.......+1/Rn
where n is number resistance.
---> dissipated [in the form of heat] in a resistance.
P=Vi=i^2R=V^2/R watts.
and the corresponding amount of energy converted to heat in time interval t2-t1 is given as
W=integral t1to t2 R i^2 dt joules.
when i is a constant quantity, I, the above may be written as W=RI^2 t joules. [when t=t2-t1]