Question

A thickness of a material is a factor that affects heat conductivity. Does heat flow faster through a thick or a thin piece of the same material?

The surface area of a material is a factor that affects heat conductivity. Does heat flow faster through a large surface area or through a small surface area? Why? (Hint:  Think about the number of particles available to bump into one another).




Change in temperature is a factor that affects heat conductivity.  Will heat flow faster when there’s a large change in temperature or a small change in temperature?

Answer 1

1. Heat flows faster through a thin material.

2. Heat flows through a large surface area.

3. Heat flows faster for a large change in temperature.

Step-by-step explanation:

Thinking process:

Newton's law of cooling or heat transfer is given by the following equation:

`Q= kA\delta T`

Where Q = Heat change (J)

A = area of hear transfer (m²)

`\fdelta`
`\delta T` = Change in temperature.

However, for a temperature difference across the wall having a thickness "x"and a constant surface area A, we get,

`Q= k.A(T_(1) - T_(2) )/(x)`

Where x = thickness of the material

As we can see, increasing the thickness, x, decreases the heat flux

Increasing the area, A increases the heat flux

A big temperature increase, ΔT results in a large heat transfer.