Nigerian Scholars » Past Questions » Physics » It takes 4 minutes to boil a quantity of water electrically. How long will it ta...

It takes 4 minutes to boil a quantity of water electrically. How long will it ta...


Question

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).

Options

A) 64 minutes

B) 32 minutes

C) 8 minutes

D) 2 minutes

E) 1 minute


The correct answer is E.

Explanation:

D ∝ l2
E will increase 4 times when current is doubled.
Therefore time will decrease by a factor of 4, which is 1 minute.

More Past Questions:


Dicussion (1)