1 mole of an ideal gas is contained in a cubical volume V, ABCDEFGH at 300 K. One face of the cube (EFGH) is made up of a material which totally absorbs any gas molecule incident on it. At any given time,
1 mole of an ideal gas is contained in a cubical volume V, ABCDEFGH at 300 K. One face of the cube (EFGH) is made up of a material which totally absorbs any gas molecule incident on it. At any given time,

a) the pressure on EFGH would be zero

b) the pressure on all the faces will the equal

c) the pressure of EFGH would be double the pressure on ABCD

d) the pressure on EFGH would be half that on ABCD

Answer:

The correct option is d) the pressure on EFGH would be half that on ABCD.

Face EFGH would have half the pressure of face ABCD. This is due to the fact that the force EFGH absorbs any molecules that come into contact with it. These molecules don’t bounce back. When compared to the force/pressure on face ABCD, where molecules rebound with the same velocity, the change in momentum causes force, and hence pressure is reduced by half.