Which of the following are physical changes?
 

i) Melting of an iron rod 

ii) Rusting of an iron rod 

iii) Bending of an iron 

iv) Hammering an iron rod into a sheet

Melting and bending of an iron rod, and hammering an iron rod into a sheet are examples of physical changes.
The substance is said to undergo physical change if the chemical composition of the substance remains unchanged. The characteristics of physical changes are: They cannot produce new substances, no new mass is produced or occurred, and no gain or loss of energy is occurred. Melting, bending, and hammering change the form of the rod but not its composition.