My research group tries to kill bacterial biofilms on medical implants by heating them up. this also heats up the surrounding tissue, damaging some of it. to study this, we have creatc artificial tissue phantoms that we can pour into a given shape and gel into a solid to study conductive heat transfer from the biofilm. we can tune the thermal conductivity of these phantoms to match the tissue we're interested in. 3) one way to measure the thermal conductivity of these phantoms is to place an electroresistive heater beneath a planar slab of the phantom, then place a sheet of melting ice on top of the phantom. we use controls software to set the heater surface at a given temperature, then measure how much electrical power takes to maintain that termperature. in one experiment, it took 1.44 w of power to maintain the 19 cm" heating element at 40 °c beneath a 1-inch-thick phantom. a) what was the thermal conductivity of that phantom? b) what was the temperature of the phantom '4 inch from the top?