An electric kettle with negligible heat capacity is rated at 2000W. If 2.0kg of water is put in it, how long will it take the temperature of water to rise from 20OC to 100OC? [specific heat capacity of water = 4200Jkg-1k-1]
-
A.
420S -
B.
336S -
C.
168S -
D.
48S
Correct Answer: Option B
Explanation
Heat energy = Elect. energy
mc(theta) = power x time
2 x 4200 x (100 – 20) = 2000 x t
t = 336s