In spot pulsed laser welding of aluminum plates (density = 2700 kg/m³, specific heat = 896 J/kg, melting temperature = 933 K, latent heat of melting = 398 kJ/kg) at a temp of 30°C, pulse with energy of 0.5 J is focused onto an area of 0.05 mm². If the entire energy is coupled into the material, what will be the depth of weld assuming the cross sectional area of the weld is circular and is uniform throughout its depth and only heat conduction in the direction of penetration.