A large panel is to be used in an aerospace application is loaded by a distributed uniaxial tensile stresses of 300 MPa. The panel has a small cut-out of circular shape to insure an internal access. Fabrication of a hole often produces very small (in comparison with the radius of the hole) edge defects. If fracture toughness of the material is 100 MPa m^1/2 , what is the sensitivity of the defect detection technique is required? (Sensitivity means the minimum size of defect that can be detected by the technique).