**1. The problem statement, all variables and given/known data**

A tank contains 125 litres of water. If it’s temperature is 20C, how long would it take for a 2kW immersion heater to raise its temperature to 60C if the average rate of heat loss is 150W?

**2. Relevant equations**

I am using the specific heat capacity equation:

ΔQ = mcΔT

**3. The attempt at a solution**

ΔQ = 125 x 4200 x 40 = 21, 000, 000 J

2kW = 2kJ per second.

Concerning Heat Loss:

2000W – 150 W = 1850 W = 1.85kW

21,000KJ = 11, 351 seconds.

11, 351 / 60 = Approximately 190 minutes.

I kind of get the feeling I’m not right. Any tips? Would be appreciated.

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