During phase change,entropy

Which of the following statements is correct for any thermodynamic system?

“Heat cannot by itself flow from a body at lower temperature to a body at higher temperature” is a statement or consequence of

$A$ measure of the degree of disorder of a system is known as

Find the change in the entropy in the following process: $100 \, g$ of ice at $0^{\circ}C$ melts when dropped in a bucket of water at $50^{\circ}C$. (Assume the temperature of the water does not change). The result is in $cal/K$.

The graphs below show the entropy versus energy $U$ of two systems $1$ and $2$ at constant volume. The initial energies of the systems are indicated by $U_{1, i}$ and $U_{2, i}$,respectively. The graphs are drawn to the same scale. The systems are then brought into thermal contact with each other. Assume that,at all times,the combined energy of the two systems remains constant. Choose the most appropriate option indicating the energies of the two systems and the total entropy after they achieve equilibrium.