Q1: Pick out the wrong statement.

ANS:C - Recrystallisation temperature decreases with decrease in strain in a cold worked metal.

Recrystallization is a phenomenon that occurs in metals that have been subjected to plastic deformation (cold working). Cold working introduces internal stresses and dislocations into the metal lattice structure, which can hinder the mobility of atoms and impede further deformation. Recrystallization is the process by which these defects are removed, and new, strain-free grains are formed in the material. Recrystallization temperature is the temperature at which recrystallization begins to occur in a cold worked metal. It is influenced by several factors, including the degree of cold work, the composition of the metal, and the presence of alloying elements. As the degree of cold work increases (i.e., higher levels of strain), the recrystallization temperature typically increases. This is because more deformation introduces more internal stresses and dislocations into the metal, which require higher temperatures to overcome and facilitate recrystallization. Conversely, decreasing the strain in a cold worked metal would generally not lead to a decrease in the recrystallization temperature. If anything, reducing the strain may slightly lower the recrystallization temperature, but this effect is usually minor compared to the overall influence of strain level. Therefore, the statement that "Recrystallisation temperature decreases with decrease in strain in a cold worked metal" is not accurate. Instead, recrystallization temperature typically increases with an increase in strain in a cold worked metal.