In: Physics
Constant amount of ideal gas is kept inside a cylinder by a piston. The piston is locked in to position, it is not allowed to move. The gas is then heated up. Compare the initial (i) and the final (f) physical quantities of the gas to each other.
(The fill in the blank options are greater than, less than, or equal too).
The volume Vf is ... Vi.
The temperature Tf is ... Ti.
The internal energy Uf is ... Ui.
The entropy Sf is ... Si.
The pressure pf is ... pi.
Constant amount of ideal gas is kept inside a cylinder by a piston.
The piston is locked in to position, it is not allowed to move. The gas is then heated up.
Compare the initial (i) and the final (f) physical quantities of the gas to each other.
(i) The volume Vf is greater than Vi.
Explanation : Volume increases in an expansion process.
(ii) The temperature Tf is less than Ti.
Explanation : Temperature will be decreased. As no heat transfer takes place. So, the work of expansion will take place with the expense of internal energy and internal energy will decrease.
Hence, temperature will be decreased as the internal energy is the sole function of temperature.
(iii) The internal energy Uf is less than Ui.
Explanation : Internal energy will be decreased because the work of expansion will take place with expense of internal energy.
(iv) The entropy Sf is less than Si.
Explanation : Entropy will decrease as the volume increases in an expansion & the randomness or the collision rate will decrease.
(v) The pressure pf is less than pi.
Explanation : Pressure will be decreased as in the adiabatic process. It is inversely proportional to the volume.
In expansion, volume increases.