GATE-2018 (24) :Wyllie – Time average equation

 27. With increasing depth in the Earth, the P-wave velocity shows a significant decrease across which one of the following boundaries?

A) crust – mantle

B) mantle – outer core

C) outer core – inner core

D) upper mantle – lower mantle

 

Solution:

A P-wave incident on the boundary between the mantle and fluid outer core is refracted towards the normal to the interface because the P-wave velocity drops from about 13 Km/s to about 8 Km/s at the boundary.

 

Answer: B

For more information please check below post:

https://gpsurya.blogspot.com/2018/05/csir-net-2017-june-94.html

_References: 

_{1. Fundamentals of Geophysics by William Lowrie.}