Question

Q. Consider the following statements with reference to interior of earth

Which of the above statements is/are correct?

• A.
  1 only
• B.
  2 only
• C.
  Both 1 and 2
• D.
  Neither 1 not 2

Answer 1

The correct option is C

Both 1 and 2
Explanation -

There are three main sources of heat in the deep earth:

All the statements are correct - There are three main sources of heat in the deep earth: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.

The outer layer is the earth crust –the lithosphere consists of 2 parts – the upper part consists of granitic rocks and forms the continents which comprises silica and alumina which have a density of 2.7.

The lower part consists of basaltic rocks and forms the oceans which comprises of silica,iron and magnesium which has average density of 3.0