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

In summary, the conversation discusses the calculation of power delivered by a 540W heating coil with a 110V nichrome wire that is 0.600mm in diameter. The question is about the variation of resistivity with temperature and how to calculate the power delivered when the coil is heated from 20C to 1200C. The suggested formula to use is R=R[o]*(1+alpha8(T-T[o]), with alpha as 0.0004 and R as the calculated ohms from wattage and volts. However, the speaker is unsure if this is the correct approach and may also need to consider the change in resistance due to thermal expansion.
  • #1
cnugrl
3
0
:confused: 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, waht 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?
 
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  • #2
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.
 
  • #3


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.
 

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

1. What is resistivity with temperature?

Resistivity with temperature refers to the measure of a material's resistance to electric current flow as its temperature changes. It is represented by the Greek letter rho (ρ) and is measured in units of ohm-meters (Ω*m).

2. How does resistivity change with temperature?

Resistivity generally increases with an increase in temperature for most materials. This is because as temperature increases, the atoms within the material vibrate more, causing more collisions and hindering the flow of electrons, leading to an increase in resistance.

3. What is the significance of resistivity with temperature?

Resistivity with temperature is an important factor to consider when designing electrical systems. It can be used to predict the behavior of materials at different temperatures and ensure that the system can handle the changes in resistance that may occur.

4. How do materials differ in their resistivity-temperature relationship?

Different materials have different resistivity-temperature relationships. Some materials, such as metals, have a positive temperature coefficient, meaning their resistivity increases with temperature. Others, like semiconductors, have a negative temperature coefficient, meaning their resistivity decreases with temperature.

5. What is the equation for calculating resistivity with temperature?

The equation for calculating resistivity with temperature is ρt = ρ0 [1 + α(Tt - T0)], where ρt is the resistivity at a given temperature (Tt), ρ0 is the resistivity at a reference temperature (T0), and α is the temperature coefficient of resistivity. This equation is known as the temperature coefficient formula.

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