For a given frequency in a material, which statement best explains why shear waves are often more sensitive to small discontinuities than longitudinal waves?

For a given frequency in a material, which statement best explains why shear waves are often more sensitive to small discontinuities than longitudinal waves?

• A. The wavelength of shear waves is shorter than that of longitudinal waves
• B. Shear waves are not as easily dispersed in the material
• C. The direction of particle vibration for shear waves is more sensitive to discontinuities
• D. The wavelength of shear waves is longer than that of longitudinal waves

Answer: (A)

For a given frequency, whether a wave can detect a small discontinuity hinges on how its wavelength compares to the flaw size. Shorter wavelengths interact with small flaws more effectively, causing stronger scattering and reflections. Shear waves travel slower in most materials than longitudinal waves, so at the same frequency their wavelength is shorter. That shorter wavelength provides higher spatial resolution, making small discontinuities more detectable. The other ideas don’t capture this fundamental point—the key factor is the shorter shear-wavelength, which enhances sensitivity to small features. If the wavelength were longer, small flaws would be harder to detect due to weaker interaction.

For a given frequency, whether a wave can detect a small discontinuity hinges on how its wavelength compares to the flaw size. Shorter wavelengths interact with small flaws more effectively, causing stronger scattering and reflections. Shear waves travel slower in most materials than longitudinal waves, so at the same frequency their wavelength is shorter. That shorter wavelength provides higher spatial resolution, making small discontinuities more detectable. The other ideas don’t capture this fundamental point—the key factor is the shorter shear-wavelength, which enhances sensitivity to small features. If the wavelength were longer, small flaws would be harder to detect due to weaker interaction.