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]
- 4.28 kg
- 42.86 kg
-
1.02 kg
- 7.14 kg
The correct answer is: C
Explanation
The energy supplied by the heater = heater gained by the water
pt = Mc\(\Delta\)θ
1000 x 300 = m x 4200(100 - 30)
m = \(\frac{(1000 \times 300)}{4200 \times 70}\) = 1.02 kg
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