What is the power delivered by a 540W heating coil at 1200C?

[cnugrl]

oki, here's the deal, i have a 540W heating coil 110V nichrome wre 0.600mm in diameter. considering the variaion of resistivity with temperature, what will the coil 4.2236 m actually deliver when it is heated to from 1200 C from 20 C. i have tried using R=R[o]*(1+alpha8(T-T[o]) and using alpha as .0004 and R as the ohms found from wattage and volts. where am i going wrong?

 

[Gokul43201]

This question is very poorly worded. Would you please write it down EXACTLY as it appears in your homework ?

If you're asking for the power delivered at 1200C, P = V^2/R(1200C) should give you the answer. You may also have to consider the change in resistance due to thermal expansion, though I think this may be small.

 

[wais]

The power delivered by a 540W heating coil at 1200C can be calculated using the formula P = V^2/R, where P is the power in watts, V is the voltage in volts, and R is the resistance in ohms. However, in this scenario, the resistance of the heating coil will change as it is heated from 20C to 1200C due to the variation of resistivity with temperature. To accurately calculate the power delivered, you will need to use the correct resistance value at 1200C.

The formula you have used, R = R[o]*(1+alpha8(T-T[o]), is correct for calculating the resistance at a specific temperature. However, you need to use the correct values for R[o] (resistance at 20C) and alpha (temperature coefficient of resistance) for your specific heating coil. The value of alpha can vary depending on the material and construction of the heating coil. Additionally, you will need to use the correct value for T (temperature in Kelvin) in the formula.

Once you have calculated the resistance at 1200C using the correct values, you can then use the formula P = V^2/R to calculate the power delivered by the heating coil at that temperature. It is important to note that this calculation will only give an estimate of the power delivered, as there may be other factors such as heat loss that can affect the actual power delivered by the coil.

In summary, to accurately calculate the power delivered by a 540W heating coil at 1200C, you will need to use the correct values for resistance at 20C, alpha, and temperature in the formula R = R[o]*(1+alpha8(T-T[o]). Once you have calculated the resistance at 1200C, you can then use the formula P = V^2/R to determine the power delivered by the heating coil.