Heat is being added to a sample of water at a constant rate. The water is initially solid, starts at -10°C and it takes 10 seconds to reach 0°C.

You may find the following data helpful when deciding which graph is correct:

Specific heats for water: c_liquid = 1.0 cal/g °C and c_ice = c_steam = 0.5 cal/g °C
Latent heats for water: heat of fusion L_f = 80 cal/g and heat of vaporization L_v = 540 cal/g

Which graph shows correctly the temperature as a function of time for the first 120 seconds?

1. Graph 1
2. Graph 2
3. Graph 3
4. Graph 4
5. Graph 5