Question

Work done in a free expansion process is (a) +ve (b) –ve (c) zero (d) none of the above

Answer 1

Answer:

First of all, let us understand the following:

WHAT IS FREE EXPANSION OF GASES ?

Let us consider a box with 2 chambers.

In one chamber, there is gas, and in the other chamber it is just empty (vacuum).

If we connect the 2 chambers, the gas in the 1st chamber will rush to fill up the space in the 2nd chamber.

This type of expansion is called free expansion.

Concept of Work Done :

Work done in thermodynamics is determined as the product of pressure and volume change.

W = P × ∆V.

Here P refers to the opposing pressure.

Calculation:

In this case of free expansion, the 2nd chamber has no gas, hence no pressure.

So P = 0

So work done = P × ∆V

=> W = 0 × ∆V

=> W = 0 Joules.

So the answer is zero ( option 3)

Refer to the attached photo to understand better.