Please help i do not understand how to answer this question

Please help, i do not understand how to answer this question.

The following procedures are available to inspect alloy steel castings in order to confirm the integrity of the casting prior to the start of machining Magnetic Particle Inspection Liquid (Dye) Penetrant Inspection Ultrasonic Inspection \" - Radiographic Inspection Provide an overview of each procedure and indicate which procedures can be used to detect surface and internal defects in the casting.

Solution

magnetic particle inspection: it is a non-distructive testing process used to detect surface and mineature subsurface discontinuities by putting magnetic field in the part,.

liquid(dye) penetrant inspection: it is a method used to locate surface-breaking defects in all non-porous materials . it is a low cost inspection. the penetrant may be applied to all non ferrous material and ferrous material.

ultrasonic inspection: it is a non-distructive testing process used to detect internal flaws or charecterize the material. it is done by ultrasonic wave propagation

radiographic inspection: it is a non-distructive testing process used to inspect the hidden flaws in the material by using short wavelength electromagnetic radiation

all the four processes are used to detect surface and internal defects.