Question

20. The vibration direction parallel to the wave direction in the vertical plane is present in,
a. P waves
b. S waves
c. Surface waves
d. L- waves

21. Volcanoes are,
a. Indirect source of information about the interior of the Earth
b. Not source of information about the interior of the Earth
c. Direct source of information about the interior of the Earth
d. Good source to ascertain earth's temperature​

Answer 1

Answer:

Q 20 The vibration direction parallel to the wa

ve direction in the vertical plane is present in. P-waves.

Q21 is d )