Solving the Resistance of an Electric Water Heater

In summary, the problem involves finding the resistance of a heating element in an electric water heater that warms 137 kg of water from 20°C to 45.0°C in 16.0 min, with a 220-V potential difference. The equation R=V/I can be used to solve for the resistance, and the power can be calculated using the equation P=V^2/R. The equation Q=mcΔT can also be used to calculate the necessary heat to warm the water.
  • #1
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Homework Statement


A well-insulated electric water heater warms 137 kg of water from 20°C to 45.0°C in 16.0 min. Find the resistance of its heating element, which is connected across 220-V potential difference.


Homework Equations


R=V/I


The Attempt at a Solution


Not sure how to approach this one. Should I refer to a calorimetry approach along with electrical relations? How might I start this one?

Any help/hints would be greatly appreciated.
 
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  • #2


There is also an equation that relates the power to the voltage V and the resistance R.
On the other hand, you should be able to calculate the power from the given data.
 
  • #3


Gotcha. Thanks for the hint. Looks like Q = mc delta T works great for calculating necessary heat to heat the water while v squared over R multiplied by time (in seconds) equals the heat generated by potential and resistance over time.

I appreciate your time in providing the hint.
 

What is the resistance of an electric water heater?

The resistance of an electric water heater varies depending on the specific model and age of the heater. However, most electric water heaters have a resistance of around 10-20 ohms.

How can I measure the resistance of my electric water heater?

To measure the resistance of an electric water heater, you will need a multimeter. Set the multimeter to the ohms setting and touch the two probes to the terminals on the water heater. The reading on the multimeter will be the resistance of the water heater.

What is considered a normal resistance for an electric water heater?

A normal resistance for an electric water heater is typically between 10-20 ohms. If the resistance is significantly higher or lower than this range, it may indicate a problem with the heating element or thermostat.

How can I troubleshoot a high resistance in my electric water heater?

If your electric water heater has a high resistance, it could be due to a faulty heating element or thermostat. You can test these components with a multimeter and replace them if necessary. It is also a good idea to check for any loose connections or wiring issues.

Can a low resistance in my electric water heater be fixed?

If your electric water heater has a low resistance, it could be caused by a buildup of sediment or mineral deposits on the heating element. This can usually be fixed by draining and flushing the tank to remove the buildup. However, if the heating element itself is damaged, it may need to be replaced.

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