Entropy (`S`) is a thermodynamic variable like pressure `P`, volume `V` and temperature `T`. Entropy of a thermodynamic system is a measure of disorder of molecular motion. Greater is disorder , greater is entropy. Change in entropy of a thermodynamic system is the ratio of heat supplied to absolute temperature.In an adiabatic reversible process, entropy remains constant while in any irreversible process entropy increases. In nature the processes are irreversible , therefore entropy of universe is continuoulsy increasing.
The unit of entropy in `S-I` system is -

Options

A. `"cal"//K`
B. `"joule"//"kg"`
C. `"joule"//"k"`
D. `"kilocal"//^(@)C`

Answer

C

Explanation

Change in entropy `DeltaS = (DeltaQ)/(T)`
`implies ` Unit of entropy = `JK^(-1)`