Consider a metal rod that has 10 W of heat conduction between its two ends, which are maintained at temperatures of 200 K and 400 K. If we raise the temperature of the hot end from 400 K to 500 K, what is the new rate of heat conduction along the rod? Group of answer choices

Respuesta :

Answer:

heat conduction along the rod ( Q/Δt ):

⇒ Q/Δt = 15 W

Explanation:

heat conduction:

  • Q/Δt = k.A.(T1 - T2)......fourier law

∴ Q/Δt : heat trasmitted per unit of time.

∴ k: thermal conductivity

∴ A: contact surface area

∴ T1 - T2: temperature difference between its two ends.

⇒ Q/Δt = 10 W

⇒ T1 = 400K ∧ 500K

⇒ T2 = 200K

∴ 10W = k.A(400K - 200K)

⇒ k.A = 10 W/200K = 0.05 W/K

if T1 = 500K

⇒ Q/Δt = (0.05 W/K)(500K - 200K)

⇒ Q/Δt = (0.05 W/K)(300K)

⇒ Q/Δt = 15 W

This question involves the concepts of Fourier's Law of heat conduction.

The new rate of heat conduction is "15 W".

Fourier's Law of heat conduction gives the rate of heat conduction through this formula:

[tex]Q=-KA\frac{\Delta T}{\Delta x}[/tex]

where,

Q = Rate of heat conduction = 10 W

K = Thermal conductivity of the material of the rod

A = Area of cross-section of rod

ΔT = change in temperature = 400 K - 200 K = 200 K

Δx = length of rod

Therefore,

[tex]\frac{10\ W}{200\ K}=\frac{-KA}{\Delta x}\\\\\frac{-KA}{\Delta x}= 0.05\ W/K\\\\[/tex]

Now, for the changed temperature only the temperature difference will change:

ΔT' = 500 K - 200 K = 300 K

Therefore,

[tex]Q' = \frac{-KA}{\Delta x}(\Delta T)\\\\Q' = (0.05\ W/K)(300\ K)[/tex]

Q' = 15 W

Learn more about Fourier's Law of heat conduction here:

https://brainly.com/question/13253422?referrer=searchResults

The attached picture shows Fourier's Law of heat conduction.

Ver imagen hamzaahmeds