Soal - Soal Thermodynamics =)

A water heater is powered by solar power. If the total area of the solar panel is 8 cm^2 and the powered delivered by the sunlight is 550 Wm^-2 , how long does it take to increase the temperature of of water from 20 C to 40 C?

One mole of an ideal gas is heated slowly in such a way that the pressure of the gas is directly proportional to its volume until the volume is twice its initial value. How much work is done during the process? How is the temperature of the gas related to its volume during this process?