How Long to Heat 250g of Water with a 250-Watt Heater?

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SUMMARY

The discussion centers on calculating the time required to heat 250 grams of water from 20°C to 80°C using a 250-watt electric heater. The temperature difference is 60°C, which translates to 15,000 calories. Converting calories to joules results in 62,760 joules. Dividing this by the heater's power output of 250 watts yields a heating time of 251 seconds, or approximately 4.18 minutes. The calculations and approach presented are confirmed as correct.

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  • Understanding of basic thermodynamics concepts, specifically heat transfer.
  • Familiarity with the calorie and joule units of energy.
  • Knowledge of power calculations involving watts.
  • Basic algebra for solving equations.
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  • Research the specific heat capacity of water and its implications in heating calculations.
  • Learn about the efficiency of electric heaters and factors affecting their performance.
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Students in physics or engineering, educators teaching thermodynamics, and anyone interested in practical applications of heat transfer calculations.

wakejosh
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Homework Statement


its a long story problem so ill break it down:
an electric heater generates 250 Watts of electricity, how long will it take for 250 grams of water to heat from 20 C to 80 C


The Attempt at a Solution



so 80 C - 20 C = 60 C , i have to heat it 60 C
250 grams of water X 60 C = 15000 Calories
4.184 X 15000 = 62760 Joules

62760 J / 250 watts = 251 seconds / 60 = 4.18 min

so it will take 4.18 min. Is this correct?
 
Last edited:
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I didn't check the math, but it looks like your approach is correct.
 

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