Two wires of the same material and lengths but having diameters in the ratio of $1:2$ are stretched by a force of equal magnitude. The ratio of potential energy stored per unit volume for the two wires when stretched will be

• Correct answer
  A

  $16:1$
• B

  $2:1$
• C

  $4:1$
• D

  $1:1$

Hence, the correct answer is option: 'A'.