Question

Consider a pan of water being heated \((a)\) by placing it on an electric range and \((b)\) by placing a heating element in the water. Which method is a more efficient way of heating water? Explain.

Short answer

Answer: An immersed heating element is more efficient at heating water compared to using an electric range, as there are fewer stages where heat loss can occur.

Step-by-step solution

Understand the problem

In this exercise, we are comparing the efficiency of two methods for heating water. Efficiency can be defined as the amount of heat transferred to the water divided by the total heat generated by the source. The method that transfers more heat to the water with less heat loss to the surroundings is more efficient.

Analyze the efficiency of heating water using an electric range

When using an electric range, the heat is generated by the electric coils beneath the pan. Heat is transferred to the pan and then to the water. There are potential heat losses in two stages: 1. Some of the heat generated by the electric coils may be lost to the surroundings without reaching the pan, and; 2. Some of the heat from the pan may be lost to the surroundings without being transferred to the water.

Analyze the efficiency of heating water using an immersed heating element

When using an immersed heating element, the heat is generated directly within the water. This method reduces the potential heat loss, as there is only one stage for heat loss: 1. Some of the heat generated by the heating element may be lost to the surroundings without being transferred to the water.

Compare the efficiencies of the two methods

Comparing the two methods, we can observe that the immersed heating element has fewer stages where heat loss can occur. Therefore, it is more efficient at transferring heat to the water.

Conclusion

An immersed heating element is a more efficient way of heating water compared to placing a pan on an electric range, as there are fewer stages where heat loss can occur.