Question

when using an 11\ extension at 90 degrees (see the picture), how much torque must be added to compensate for the length of the extension?
5% for any extension between 6 - 12 inches long
1% - per inch of extension
none - there is no compensation needed
1 in - lb - per inch of extension

Explanation:

When using a torque - wrench with an extension at 90 degrees, the general rule is to add 1% of the specified torque per inch of extension length. Here the extension is 11 inches long.

Answer:

1% - per inch of extension