Explain the expression for the equivalient resistance of three resistors which are connected in series.\

Explanation

Series connection :
In series connection of resistors there is only one path for the flow of current in the circuit. Hence, the current in the circuit is equal to I.
According to Ohm's law,
`thereforeV_(1)=IR:V_(2)=IR_(2)andV_(3)=IR_(3).`
`rArr` Let R be the equivalent resistance of the combination of resistors in series.
`" Also "V=IR_(eq)`
`V=V_(1)+V_(2)+V_(3)`
`IR_(eq)=IR_(1)+IR_(2)+IR_(3)`
`rArrcancel(I)R_(eq)=cancel(I)(R_(1)+R_(2)+R_(3))`
`rArrR_(eq)=R_(1)+R_(2)+R_(3)`
`therefore` The sum of individual resistance is equal to their equivalent resistance when the resistors are connected in series.