Question

An Aluminium bar is 3.25m long and has a diameter of 25mm. If the temperature difference between the ends is 250°C, find the rate of heat transfer along the bar. (Where the Thermal conductivity for Al is 205W/m°C)

is it 5.67 W, 7.74 W, or 10.5 W?

Answer 1

Answer

7.74 W

Explanation

The formula for getting the the rate of heat transfer is:

$\frac{Q}{T}$=$\frac{KA(T2 - T1) }{d}$

A = πr² = π×(12.5/1000)²

            = 4.908×10⁻⁴m²

Rate of heat transfer   = $\frac{205*4.908×10⁻⁴*250}{3.25}$

                                      = 7.74 W