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 frequency decreases.
B.
the wave's speed increases.
C.
the wave's frequency increases.
D.
the wave's speed decreases.

Answer 1

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

B. the wave's speed increases.

In general, seismic waves travel faster through denser materials, and as pressure increases in the Earth's mantle, it causes the materials to become denser, thus increasing the speed of the seismic wave.