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?

- Graph 1
- Graph 2
- Graph 3
- Graph 4
- Graph 5