Which statement best describes calibration?

• A. It increases the beam spread
• B. It reduces noise
• C. It ensures instrument readings are accurate by comparison with a standard
• D. It extends instrument range

Answer: (C)

Calibration is the process of aligning the instrument’s readings with a known reference so the results reflect true values. By comparing what the instrument shows to a standard and adjusting the system accordingly, you establish accuracy and traceability over time. This is why the statement that calibration makes instrument readings accurate by comparison with a standard is the best choice. It isn’t about widening the ultrasonic beam, reducing random noise, or extending the instrument’s stated measurement range—those are governed by different aspects of the hardware and signal processing. In practice, calibration in UT uses reference standards or blocks to set sensitivity, timing, and velocity so measurements stay consistent and reliable.