An electric kettle has a power of 1.2kw. How long will it take to heat 3 kg of water to the from 20¡ãC to 100¡ãC?

First find the energy you need

E = mc(Tf-Ti)
Then P = E/t
solve for t.

To determine how long it will take to heat the water, we need to use the equation:

Energy = Power × Time

First, let's calculate the energy required to heat the water. The specific heat capacity of water is approximately 4.18 J/g°C. Since we have 3 kg of water, we can calculate the energy using the formula:

Energy = Mass × Specific Heat Capacity × Change in Temperature

Change in Temperature = Final Temperature - Initial Temperature = 100°C - 20°C = 80°C

Energy = 3 kg × 4.18 J/g°C × 80°C = 1008 J/g

Now, let's convert the energy to kilojoules:

Energy = 1008 J/g ÷ 1000 = 1.008 kJ/g

Next, we can rearrange the equation to solve for time:

Time = Energy ÷ Power

Time = 1.008 kJ/g ÷ 1.2 kW = 0.84 seconds

Therefore, it will take approximately 0.84 seconds to heat 3 kg of water from 20°C to 100°C using an electric kettle with a power of 1.2 kW.