An engineer uses an ultrasound transducer to perform non-destructive testing on a thick glass-fibre reinforced polymer (GFRP) wind turbine blade.
In a healthy, defect-free section of the blade, the transducer transmits an ultrasound pulse at time t=0t = 0t=0 and subsequently detects a single clear, high-amplitude reflected pulse RB R_B\,RB from the rear boundary of the polymer section.
In a section containing a localized internal delamination (a narrow air gap between composite layers), the transducer detects a very low-amplitude reflected pulse RD R_D\,RD at an earlier time, followed by a pulse of reduced amplitude from the rear boundary.
Suggest one physical reason why the amplitude of the pulse reflected from the delamination defect (RDR_DRD) is significantly smaller than the amplitude of the pulse reflected from the rear boundary of the healthy section (RBR_BRB).
35 exam-style questions on Edexcel GCSE Physics 4.3 Sound, ultrasound and infrasound, covering 4.3.1 Sound waves, vibrations and the human ear, 4.3.2 Ultrasound and infrasound, 4.3.3 Uses of ultrasound and infrasound, and 4.3.4 Sound waves passing between media. Each one has a worked solution and a mark scheme showing where the marks go.