Obtain an expression for equivalent resistance of two resistors connected in a series combination.

Explanation

Two resistors of resistance `R_(1)` and `R_(2)` are connected in series. Let I be the current flowing through the circuit The current through each resistor is also I. The two resistors joined in series is replaced by an equivalent single resistor of resistance R such that the potential difference V across it, and the current I through the circuit remains same.

As `V=IR , V_(1)=IR =IR_(1),V_(2)=IR_(2)`
`IR=IR_(1)+IR_(2)`
`IR=I (R_(1)+R_(2)) or R= R_(1)+R_(2)` .