Final answer:
A strain gauge is an electrical device that measures strain by detecting changes in resistance. Each reading from the strain gauge represents the strain values in different directions or orientations.
Step-by-step explanation:
A strain gauge is an electrical device that measures strain by detecting changes in resistance. When a strain gauge is attached to the surface of a stressed component, it gives readings of εₐ, ε₆, and εc. These readings represent the strain values in different directions or orientations.
For example, if εₐ equals A, ε₆ equals B, and εc equals C, it means that the strain gauge measures strain values A in one direction, B in another direction, and C in the final direction.