If the tension on a wire is removed at once, then 

CONCEPT:

• Tension is a kind of Force applied to a string or wire along the length from both ends to stretch it.
  • SI unit of Tension is Newton.

EXPLANATION:

• When Tension on a wire is applied, due to forces from both ends the distance between its atoms increases.
• The increase in distance between the atoms results in an increase in their Potential Energy.
• Now, if the Tension is removed at once, the potential energy decreases and converts into heat energy.
• Hence, if the tension on a wire is removed at once, then its temperature increases.