A 50 cm long, 800 W electric resistance heating element with diameter 0.50 cm and surface temperature 120°C is immersed in 40 kg of water initially at 20°C. Determine how long it will take for this heater to raise the water temperature to 80°C. Also, determine the convection heat transfer coefficients at the beginning and at the end of the heating process. Find: How long (????) it takes to raise the temperature of the water from ???????? to ????????, as well as the initial and final transfer coefficients (???? ?????? ????).