A sample of ideal gas is confined to the left half of a rigid
PHYSICS · Single correct · A Level · Physics · Engineering physics · Engineering physics
Problem
A sample of ideal gas is confined to the left half of a rigid, thermally insulated container by a partition; the right half is vacuum. At time t=0 the partition is removed, and the gas expands freely until it fills the entire volume.
Which of the following qualitative sketches best represents the total entropy S of the gas as a function of time t?
(a) S remains constant throughout the process because no heat is exchanged with the surroundings.
(b) S increases linearly with time without bound because the gas continues to expand indefinitely.
(c) S rises quickly at first and then gradually approaches a constant maximum value as t increases.
(d) S jumps instantaneously to a higher value at t=0 and then stays constant afterward.