It takes 4 minutes to boil a quantity of water electrically. How long will it take to boil same quantity of water using the same heating coil but with the current doubled? (neglecting any external heat loss).
- 64 minutes
- 32 minutes
- 8 minutes
- 2 minutes
-
1 minute
The correct answer is: E
Explanation
D ∝ l2E will increase 4 times when current is doubled.
Therefore time will decrease by a factor of 4, which is 1 minute.