To boil a certain mass of water, a coil will take a time of `t_(1)` and another coil will take a time of `t_(2)`. What will be the time taken when the coils are connected in (i) series (ii) in paralle?

Explanation

(i) In series `H=(V^(2))/(R ).t`
As H, V and are constants, `R prop t`
`"In series, "R=R_(1)+R_(2)" "therefore t_(s)=t_(1)+t_(2)`
(ii) In parallel `R=(R_(1)R_(2))/(R_(1)+R_(2))" "therefore t_(p)=(t_(1)t_(2))/(t_(1)+t_(2))`