Calculating Microwave Energy Deposition for Melting Ice and Boiling Water

In summary, the question asks how long it would take to melt a piece of ice and boil the resulting water using a microwave oven. The given data includes the microwave wavelength, peak magnetic field, ice size, and mass of the glass container. To determine the time needed, one must calculate the required heat and energy, as well as the rate of energy deposition from the microwave system.
  • #1
Xamfy19
60
0
I have trouble figuring out the following question. Please help.
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Suppose you want to melt a piece of ice and boil the resulting water by using a microwave oven. The radiation is incident upon one side of the ice which has a cross sectional area of 0.00010 m^2. The microwave only heat the ice and not the glass container. The following data are given:
Microwave wavelength: 0.122 m
Peak Magnetic field of microwaves = 1.3 * 10^-5 T
Ice is a cube with sides equal to 0.010 m
Radiation is only incident upon one side of the ice.
Mass of glass container = 0.20 kg
Initial temperature of ice = 0 degree C

How long do you need to run the Microwave Oven to melt the piece of ice and get the resultant water to boil (assume all heating goes into the water and the incident area remains constant).

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I calculated the requred heat is 1505.8 J. I thought of using Energy stored per unit volume equation (1/2 B^2/uo). However, I can't connect this result to the total energy required. I also tried to use E = hf. But it only gives me the energy of one photon.

Thanks alot.
 
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  • #2
One has to calculate the mass of the ice and then multiply it by the specific energy required to melt the ice (solid to liquid - heat of formation) and raise it to boiling (0-100°C).

The one has to determine the rate of energy deposition from the microwave system in order to determine the time.
 
  • #3
Thanks, Astronuc;
I did figure out the energy required to melt ice and water from 0 to 100, which is 1505 J. However, I do have problem determining the rate of energy deposited from microwave. I couldn't find any time-related data (or I just didn't know it) so that it can be used in calculating the rate of energy.
 

Related to Calculating Microwave Energy Deposition for Melting Ice and Boiling Water

1. How do microwaves melt ice?

Microwaves work by generating electromagnetic radiation that causes the water molecules in the ice to vibrate and gain energy. As a result, the ice molecules lose their structural integrity and the ice melts into liquid water.

2. Can microwaves melt all types of ice?

Yes, microwaves can melt all types of ice as long as there is enough water present for the microwaves to interact with. However, it may take longer to melt larger or denser ice blocks compared to smaller pieces of ice.

3. Is it safe to use a microwave to melt ice?

Yes, it is safe to use a microwave to melt ice as long as you follow proper precautions and use the microwave as directed. It is important to use microwave-safe containers and avoid overheating the ice, which can potentially cause hot spots and lead to explosions.

4. How long does it take for a microwave to melt ice?

The time it takes for a microwave to melt ice can vary depending on the size and density of the ice, as well as the power of the microwave. In general, it can take anywhere from 30 seconds to a few minutes to melt a small amount of ice in a microwave.

5. Can microwaves be used to freeze water?

No, microwaves are not capable of freezing water. Microwaves work by adding energy to water molecules, causing them to vibrate and gain energy. Freezing, on the other hand, is the process of removing energy from water molecules, causing them to slow down and form solid ice.

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