A seismic wave is traveling through the Earth's mantle. The deeper into the mantle the wave goes, the greater the pressure is.

Question

As the pressure in the mantle increases,
A.
the wave's speed increases.
B.
the wave's frequency decreases.
C.
the wave's speed decreases.
D.
the wave's frequency increases

Answer 1

As the pressure in the mantle increases, the wave's speed increases. Therefore, the correct answer is:

A. the wave's speed increases.

In general, seismic waves travel faster in denser and more rigid materials, which corresponds to the increased pressure at greater depths in the Earth's mantle.