A wire fixed at the upper end stretches by length by applying a force . The work done in stretching is:
Step 1: Given data and formula used
Let, The area be .
Stretch length =
The work done by the force is
Step 2: Determine the work done
The work done in stretching is equal to half of the product of stretching force and the increase in length.
By substituting the values in the above formula,
Therefore, the work done in stretching is .
Hence, option (D) is the correct answer.