Waves For Detection And Exploration (physics Only) (ht Only) (GCSE Physics)

A subsurface feature is detected by reflected waves arriving later than expected. Which change in the medium most likely causes the reflection arrival to be delayed?

A surveyor uses two-way travel time of a seismic reflection from a horizontal layer. If the one-way travel time to the layer is 0.20 s and seismic speed in the medium is 2000 m/s, what is the depth?

Which detection method is most appropriate for mapping shallow archaeological ruins a few meters below ground with high spatial detail?

A ground-penetrating radar (GPR) pulse has a round-trip time to a buried object of 1.0 × 10^-8 s in soil where pulse speed ˜ 1.5 × 10^8 m/s. What is the burial depth?

A wave has frequency 2.5 kHz and wavelength 0.20 m. What is its speed?

A naval sonar emits a 20 kHz pulse and listens for the echo. If the sea sound speed is 1500 m/s, what is the wavelength of the sonar pulse?

In seismic exploration, why do S-waves not travel through the outer core of the Earth?

Why are higher frequencies (shorter wavelengths) sometimes NOT used for very deep seismic exploration?

An ultrasonic pulse is sent vertically down into water and the echo from the seabed returns 0.40 s later. If the speed of sound in seawater is 1500 m/s, how deep is the seabed?

A continuous sound source and an observer move relative to each other. Which best describes the Doppler effect?

What is the principal advantage of using arrays (many detectors) and beamforming in exploration systems (e.g., sonar, radar, seismology)?