When resistres of resistyences `R_(1)R_(2) and R_(3)` are connected in series , then the resistance`R_(1)` is given by `R_(1) = R_(1) + R_(2) +R_(3)`
In this arrengement the current through each resister is same hut potential difference across then is difference
When resitorce of resistance `R_(1)R_(2) and R_(3)` are connected in particle the effective resistance `R_(p)` is given by `(1)/(R_(p)) = (1)/(R_(1)) + (1)/(R_(2)) + (1)/(R_(3))`
In this arrangement , the potential difference across each resistance is but current through then is difference
Read the above passage and answer the following question :
(i) Why does the effective resistance increase in series ?
(ii) Why does the effective resistance decrease in parallel ?
(iii) What basic value are displayed by the above study ?

Explanation

(i)When resistance are connected in series , there is only one channel for the flow currect .Due to it , the effective puth length (l) for current increase .As resistance `R prop 1` hence effective resistance increase
(ii) When resistance are connected in parallel , there are difference channel for the flow of current due to it the effective area of cross- series `(A)` of the parallel of resistance increase As `R prop 1//A` so the effective resistance decrease.
(iii) In day life , resistance corresponding and current corresponding to the output from the source
When resistance are is series oppsition increase and output reduces
When resistance are ibn parallel each is in direct with source of current the opposition decrease and the output increase .Thus to achives best resites every inember must be in direct contact with the source//family head.