Question

At certain depths in the Earth’s interior, waves are reflected and refracted. Which inference soundly relates to this phenomenon? 
A. The outer core is liquid.
B. The Earth has a dense crust.
C. The Earth has a layered interior.
D. The mantle is denser underneath.

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Answer 1

Answer: The outer core is liquid

Answer 2

The answer is Option D. The mantle is denser underneath.

• The Earth's interior structure is made of the Core, the Mantle and the outer Crust.
• These layers have different compositions and densities of rocks, due to which the waves are reflected and refracted.
• This is the principle behind seismography where the seismic waves due to earthquakes are recorded due to their bending of paths.
• This bending of the seismic waves is called refraction.
• The outward bending of these waves when they travel through the mantle suggests its increased density of rocks with its depth.
• When they travel down the core, they slow down which suggests the difference in the composition of the core and that it may be more liquid compared to the solid nature of the other zones.

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