Q. Which technique is not suitable to measure large diameter parts or large gaps?
✅ Correct Answer: (A)
diffraction pattern technique
Explanation: diffraction pattern technique is not suitable for diameters larger than few mm and is used to measure small gaps and small diameter parts. in this method, a parallel laser beam which is coherent is diffracted by a small part, and the resultant pattern is focussed on a linear diode array by a lens.