Acarpenter builds an exterior house wall with a layer of wood 3.0 cm thick on the outside and a layer of styrofoam insulation 2.4 cm thick on the inside wall surface. the wood has k=0.080w/(m? k), and the styrofoam has k= 0.010 w/(m? k). the interior surface temperature is 20.0 ? c , and the exterior surface temperature is -13.0 ? c

a.) what is the temperature at the plane where the wood meets the styrofoam? celsius
b.) what is the rate of heat flow per square meter through this wall? /m^2

A. T=15.54 °C

B. Q/A= 0.119 W/m2

Explanation:

To solve this problem we need to use the Fourier's law for thermal conduction:

Here, the rate of flow per square meter must be the same through the complete wall. Therefore, we can use it to find the temperature at the plane where the wood meets the Styrofoam as follows:

Then, to find the rate of heat flow per square meter, we have:

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia