Find the time needed to warm the water to a temperature

• MaiteB
In summary, to warm water from 20 degrees Celsius to 120 degrees Celsius, it would take an electrical resistance of 1 kW of power for 1 hour.
MaiteB

Homework Statement

An electrical resistence has a power of 1 kW. It is put inside a container that has 10 liters water. The water is in temperature 20C with pressure 1 atm. Find the time to warm the water to the temperature 120C

A=P*t

The Attempt at a Solution

I thought to use the equation p1/T1=p2/T2 and t=P/A. How can i find A?

Hello MB,

Well, if A is P*t, then writing t = P/A seems a little strange !

So perhaps you can shed a little light here ? First of all, what are these symbols representing ? And their dimensions ?

Warming up water takes heat, energy. The more energy per unit of time (a.k.a. power), the faster it goes.

Furthermore, they tell you the 10 liters of water are at a temperature of 20 ##^\circ##C in a container at a pressure of 1 atm. They don't tell you if the container is closed and kept at a constant volume, or if it's open. In other words, what happens at a temperature of, say, 100 ##^\circ##C ?

Oh, and your thread will soon be moved to the introductory physics section by the good spirits that watch over PF
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Last edited:
MaiteB said:

Homework Statement

An electrical resistence has a power of 1 kW. It is put inside a container that has 10 liters water. The water is in temperature 20C with pressure 1 atm. Find the time to warm the water to the temperature 120C

A=P*t

The Attempt at a Solution

I thought to use the equation p1/T1=p2/T2 and t=A/P. How can i find A?
I corrected it. t-time, A-work, P-power

Good (although I don't see it anywhere).
What about the p1T1 = p2T2 ? what are they ?
Can you write an equation to calculate how much energy is needed to heat up 10 liters of water by one degree C ?

1. How can I calculate the time needed to warm water to a specific temperature?

The time needed to warm water to a specific temperature can be calculated using the following formula: time = (mass of water) x (specific heat of water) x (change in temperature) / (power of heating device). This equation takes into account the mass of the water, the specific heat of water (which is 1 calorie/gram °C), the desired change in temperature, and the power of the heating device being used.

2. What factors can affect the time needed to warm water to a certain temperature?

Several factors can affect the time needed to warm water to a certain temperature, including the starting temperature of the water, the power of the heating device, the size and shape of the container holding the water, and the surrounding temperature. Additionally, the type of heating method (e.g. stovetop, microwave, etc.) and the type of water (e.g. distilled, tap, seawater) can also impact the time needed.

3. Can the time needed to warm water be shortened?

Yes, the time needed to warm water can be shortened by increasing the power of the heating device, using a smaller and more efficient container, and starting with hot water rather than cold water. Covering the container with a lid can also help to retain heat and speed up the warming process.

4. How does the altitude affect the time needed to warm water?

The higher the altitude, the lower the air pressure, which means that water boils at a lower temperature. This can affect the time needed to warm water, as it will take longer for the water to reach the desired temperature at higher altitudes. For example, water will boil at around 202°F at an altitude of 5,000 feet, compared to 212°F at sea level. This can impact the time needed to warm water on a stovetop or using other heating methods.

5. Can I use the same calculation for different types of liquids?

No, the specific heat and other properties of different liquids can vary, so the calculation for determining the time needed to warm water may not be applicable to other liquids. It is best to research and use the specific heat and other relevant factors for the specific liquid you are trying to heat.

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