A tile-iron consists of a massive plate maintained at 150°C by an embedded electrical heater. The iron is placed in contact with a tile to soften the adhesive, allowing the tile to be easily lifted from the subflooring. The adhesive will soften sufficiently if heated above 50°C for at least 2 min, but its temperature should not exceed 120°C to avoid deterioration of the adhesive. Assume the tile and subfloor to have an initial temperature of 25°C and to have equivalent thermophysical properties of k = 0.15 W/(m∙K) and rhoCp = 1.5⨯106 J/(m3 ∙K).

a) How long will it take a worker using the tile-iron to lift a tile? Will the adhesive temperature exceed 120 degrees C?b) If the tile-iron has a square surface area 254mm to the side, how much energy has been removed from it during the time it has taken to lift the tile?