An aerospace engineer performs non-destructive testing (NDT) on a titanium alloy bulkhead using an ultrasound transducer. The acoustic impedance of the titanium alloy is ZTi=2.7×107 kg m−2 s−1Z_{\text{Ti}} = 2.7 \times 10^7 \text{ kg m}^{-2}\text{ s}^{-1}ZTi=2.7×107 kg m−2 s−1.
To inspect the component effectively, the ultrasound wave must be transmitted through the interface. The engineer compares two coupling options at the interface as shown in the diagram:
- Air coupling: Zair=4.0×102 kg m−2 s−1Z_{\text{air}} = 4.0 \times 10^2 \text{ kg m}^{-2}\text{ s}^{-1}Zair=4.0×102 kg m−2 s−1
- Water coupling: Zwater=1.5×106 kg m−2 s−1Z_{\text{water}} = 1.5 \times 10^6 \text{ kg m}^{-2}\text{ s}^{-1}Zwater=1.5×106 kg m−2 s−1
Which of the following options correctly identifies the percentage of the incident wave intensity transmitted into the titanium bulkhead for each coupling medium?
Air coupling transmits ≈0.01%\approx 0.01\%≈0.01% of the intensity, while water coupling transmits ≈11%\approx 11\%≈11% of the intensity.
Air coupling transmits ≈0.01%\approx 0.01\%≈0.01% of the intensity, while water coupling transmits ≈20%\approx 20\%≈20% of the intensity.
Air coupling transmits ≈1.5%\approx 1.5\%≈1.5% of the intensity, while water coupling transmits ≈94%\approx 94\%≈94% of the intensity.
Air coupling transmits ≈11%\approx 11\%≈11% of the intensity, while water coupling transmits ≈80%\approx 80\%≈80% of the intensity.
Wave interactions Questions
Practise OCR GCSE Physics Wave interactions with exam-style questions for Foundation and Higher tier. 34 questions, matched to the OCR GCSE Physics (J249) specification and written in Paper 1 and Paper 2 (Foundation Tier) or Paper 3 and Paper 4 (Higher Tier) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.