The temperature of a gas stream is to be measured by a thermocouple whose junction can be approximated as a 1.2-mm-diameter sphere. The properties of the junction are k = 35 W/m·K, ρ = 8500 kg/m³, and c_p = 320 J/kg·K, and the heat transfer coefficient between the junction and the gas is h = 90 W/m²·K. Determine how long it will take for the thermocouple to read 99 percent of the initial temperature difference.