An electric heater rated 220v, 1000 w is immersed into a bucket full of water, calculate the mass of water if the temperature changes from 30°c to 100°c and the current flows for 300seconds.
[specific heat capacity of water = 4200 jkg-1 K-1]
[specific heat capacity of water = 4200 jkg-1 K-1]
-
A.
4.28 kg -
B.
42.86 kg -
C.
1.02 kg -
D.
7.14 kg
Correct Answer: Option C
Explanation
Energy supplied bythe heater = heater gained by water
pt = MCAθ
1000 x 300 = m x 4200(100 – 30)
m = (1000 x 300)/4200 x 70 = 1.02 kg