Question

Which of the following is/are direct source(s) of information about the interior of the Earth? 

1. Earthquake wave 

2. Volcano 

3. Gravitational force 

4. Earth magnetism 

Select the correct answer using the codes given below 

(a) 1 and 2 (b) Only 2 (c) 3 and 4 (d) All of these

Answer 1

(a) Earthquake waves are propagating vibrations that carry energy from the source of the shaking outward in all directions. It is of four types: 

P (for primary) S (for secondary) 

Love Rayleigh 

A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur.