An immersion heater is put into some crushed ice at 
. The immersion heater is switched on as shown below.
Sketch the graph of temperature against time, up to the time when all the ice has melted
The heater is left switched on after all the ice has melted, and the temperature rises. After some time, the temperature stops rising, even though the heater is still on.
Suggest why the temperature stops rising, even though the heater is still on.
State what happens to the energy received by the water whilst this is happening.
