In a scenario with multiple transmitted frequencies, the reflections would reach the transducer at which times?

In a scenario with multiple transmitted frequencies, the reflections would reach the transducer at which times?

• A. Nearly identical transmit times
• B. Different times depending on frequency
• C. Earlier for higher frequency
• D. Later for higher frequency

Answer: (A)

The key idea is that the round-trip travel time of an echo depends on the distance to the reflector and the speed of sound in the medium, not on the frequency of the transmitted pulse. In tissue, the speed of sound is effectively the same across different frequencies, so echoes from the same reflector return after the same travel time. That means reflections arrive at nearly identical times, even when multiple frequencies are used. In practice, there can be tiny dispersion, but it’s negligible for standard medical ultrasound, so the timing remains essentially the same. The other options would imply frequency-dependent speeds or path lengths, which isn’t how propagation in tissue works.

The key idea is that the round-trip travel time of an echo depends on the distance to the reflector and the speed of sound in the medium, not on the frequency of the transmitted pulse. In tissue, the speed of sound is effectively the same across different frequencies, so echoes from the same reflector return after the same travel time. That means reflections arrive at nearly identical times, even when multiple frequencies are used.

In practice, there can be tiny dispersion, but it’s negligible for standard medical ultrasound, so the timing remains essentially the same. The other options would imply frequency-dependent speeds or path lengths, which isn’t how propagation in tissue works.