Question

Match the descriptions listed in Column I with the corresponding non-destructive testing methods listed in Column II.

Column I	Column II
(P) Internal flaws in railroad wheel	(1) Ultrasonic
(Q) In-service monitoring of crack	(2) Radiography
(R) Inclusion in mild steel	(3) Dye Penetrant
(S) Surface crack in Al-based alloy	(4) Acoustic Emission

• A. P-1, Q-4, R-2, S-3
• B. P-3, Q-2, R-4, S-1
• C. P-3, Q-2, R-1, S-4
• D. P-1, Q-3, R-4, S-2

Hint:

Decide whether each defect is internal or surface breaking, and whether the check is one-time or continuous, before matching the method.

Answer 1

The Correct Option is A

Step 1: Recall what each NDT method is best suited for.
Each non-destructive testing (NDT) method in Column II has a specific strength: some find internal flaws, some track cracks while a component stays in service, and some find only surface-breaking defects.

Step 2: Match P (Internal flaws in a railroad wheel).
Ultrasonic testing sends high-frequency sound waves through the thickness of a part and picks up reflections from internal discontinuities. A railroad wheel is a thick, solid steel component, so ultrasonic testing is the standard method for checking internal flaws deep inside it. So P matches entry (1), Ultrasonic.

Step 3: Match Q (In-service monitoring of a crack).
Acoustic emission testing listens for the transient elastic stress waves released when a crack grows or a defect moves under load. Since it can run continuously while the part is in service and under load, it is the method used for real-time, in-service crack monitoring. So Q matches entry (4), Acoustic Emission.

Step 4: Match R (Inclusion in mild steel).
Radiography passes X-rays or gamma rays through a part and records the image on film or a detector; a subsurface inclusion, being denser or less dense than the surrounding steel, shows up as a contrast change on the radiograph. This makes radiography the natural choice for finding an internal inclusion in mild steel. So R matches entry (2), Radiography.

Step 5: Match S (Surface crack in an Al-based alloy).
Dye penetrant testing lets a colored or fluorescent liquid seep into a surface-breaking crack by capillary action and then draws it back out with a developer, making the crack visible. It can only find defects open to the surface, which fits a surface crack in an aluminum-based alloy. So S matches entry (3), Dye Penetrant.

Step 6: Combine and check against the options.
The complete match is P-1, Q-4, R-2, S-3, which is exactly option (A).
\[ \boxed{P\text{-}1,\ Q\text{-}4,\ R\text{-}2,\ S\text{-}3} \]