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 (k = 35 W/m·°C, ρ = 8500 kg/m^{3}, c_{p} = 320 J/kg·°C). The heat transfer coefficient between the junction and the gas is 65 W/m^{2}·°C. Determine how long it will take for the thermocouple to read 99 % of the initial temperature difference (answer in s).