A sample of gas confined in a cylinder with a movable piston is kept at constant pressure. The volume of the gas doubles when the temperature of the gas is changed from
(1) 400. K to 200. K (3) 400.°C to 200.°C
(2) 200. K to 400. K (4) 200.°C to 400.°C
When the pressure is constant, the temperature and volume of the gas has ratio relationship: V1/T1= V2/T2. And the temperature using unit of K. Then we can get the answer is (2) 200 K to 400 K.
