An electric kettle has two coils of same power . When one coil is switched on , it takes `15 min` to boil water , and when the second coil is switched on , it takes `30 min`. How long will it take to boil water when both the coils are used in `i`. Series and `ii`. parallel?A. `9:2`B. `2:9`C. `4:5`D. `5:4`

An electric kettle has two coils of same power . When one coil is swit

1.	An electric kettle has two coils of same power . When one coil is switched on , it takes `15 min` to boil water , and when the second coil is switched on , it takes `30 min`. How long will it take to boil water when both the coils are used in `i`. Series and `ii`. parallel?A. `9:2`B. `2:9`C. `4:5`D. `5:4`
Answer» Correct Answer - A `t_(S)=t_(1)+t_(2),t_(P)=(t_(1)t_(2))/(t_(1)+t_(2))`

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