Which one of the following NDT techniques cannot be used to detect an internal crack in a steel shaft?

A. increasing the size of the sample B. smooth polishing of the surface of the sample C. having compressive residual stresses at the surface D. having tensile residual stresses at the surface

A. Providing a contrasting background for visible dye indications B. Making the penetrant water washable C. Penetrating into discontinuities open to the surface D. Dissolve organic soils on the test piece surface

A. Increases, increases B. Increases, decreases C. Decreases, increases D. Decreases, decreases

A. Square based diamond pyramid with 136° included angle B. Conical shape steel with 120° apex angle C. Conical shaped diamond with 120° apex angle D. 10 mm diameter hardened steel ball