1. Define geology?

A. Geology is a science and it deals with the study of earth.

                Geo means-earth

                 Logy means-science

2. Define petrology?

A. Petrology means study of rocks.

     Petro means-rock

     Logy means-study

            (Or)

   Combination of petrology and petrogeny is known as petrology.

     

3. Define geological agents?

A. The natural forces which are responsible for the visible changes on the earth surface is called geological agents.

4. Define degradation?

A. The continuous removal of material from hills, mountains reduces their height bit by bit and ultimately their topographic levels become equal to their surroundings. This phenomenon is known as degradation.

5. Define aggradation?

A. Due to continuous deposition hills, mountains are gradually filled up, there by increasing their depths slowly bi by bit. Finally the topographic level becomes equal to the surroundings. This phenomenon of rising of the sea or lake bottom or their depth reducing may be described as aggradation.

6. Define gradation?

A. Due to degradation and aggradation the topographic elevations and depressions disappear leading to the development of plain ground is known as gradation.

7. Define erosion?

A. The process of removal of weathered materials from the place of its formation is called erosion.

8. Define weathering?

A. The process of disintegration and decomposition which is instrumental in the break down or reduction of size of rocks is known as weathering.

9. Define denudation?

A. The process of exposing fresh country rocks to the surface due to the removal of their overlaying weathered material is known as denudation.

10. Define mineral?

A. A mineral may be defined as a natural, inorganic, homogeneous, solid substance having a definite chemical composition and regular atomic structure.

11. Define crystal?

A. It mat be defined as a natural solid body bounded by smooth and plain surfaces, arranged in an orderly pattern which is an outward expression of a regular , internal atomic structure.

12. Define streak?

A. The co lour of the mineral powder is called the streak of a mineral.

13. Define distortion?

A. Sometimes crystals develop faces of different sizes and shapes. This kind of geometrical irregularity in the shape of crystals is called distortion.

14. Write down the types of geological agents?

A. 1.Exogeneous geological agents

     2. Endogenous geological agents

15. Write down the requirements of a mineral?

A. 1. It must have been formed by natural forces.

     2. It must be an inorganic substance.

     3. It must be homogeneous.

     4. It must be solid.

     5. It must be crystalline.

16. Define hydrolysis?

A. Decomposition of minerals, instead of the water molecule, only the hydrogen part of water enters into the mineral structure. This is called hydrolysis.

17. Write down the types of weathering process?

A. 1. Disintegration

      2. Decomposition

18. Hardness of mica      2