Extra configurational entropy can also be introduced into the surface by the formation of surface vacancies. Entropy effects γ is slightly dependent on temperature and is given as, γ = -2T+2. Calculate the entropy S from the given condition?

Correct Answer: -2
The entropy S can be determined using the equation, ∂γ/∂T = -S. Measured values of S are positive and vary between 0 and 3mJ m-2K-1.Hence once we differentiate it with respect to temperature we get the required value.