A solid body of constant heat capacity 1J/°C is being heated by keeping it in contact with reservoirs in two ways: (i) Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies the same amount of heat. (ii) Sequentially keeping in contact with 8 reservoirs such that each reservoir supplies the same amount of heat. In both cases, the body is brought from an initial temperature of 100°C to a final temperature of 200°C. Entropy change of the body in two cases respectively is:

The entropy change from State A to B is given by ΔS = ∫AB dQ/T.. (i) where dQ is heat supplied in J to the body and temperature is in K
TA = 273 + 100K = 373K; TB = 273 + 200 = 473K
dQ = CdT where C is heat capacity of body and dT is increase in temperature in °C
Substituting T′ = T - 273 in equation (i) where T′ is temperature in °C and T is in kelvin. dT′ = dT
integration limits: T′A = 373 - 273 = 100°C; T′B = 473 - 273 = 200°C
ΔS = ∫100200 CdT′/(T′ + 273) = C ln(473/373)
As the heat transferred is the same, the entropy change will be the same in both cases