There are mainly two approaches to geography. The first one is the systematic approach and the second one is the regional approach.
The systematic approach studies only one issue and continues to examine its spatial variations. That means related to different spaces, you study your location.
On the other hand, the regional approach studies the multiple characteristics after dividing or segmenting the location at hand, on the basis of region. Meaning you divide your location into regions, next you study characteristics of each region.

There is a time lag of 2 hours from Gujarat to Arunachal Pradesh it means the sunrise two hours earlier in Arunachal Pradesh as compared to Gujarat in the west but the watches choose the same time the Earth takes 4 minutes to rotate 1 Degree of longitude therefore the time taken by the earth to rotate through 1 Degree of longitude is 4 minutes then 15 degree longitude will be 1 hour scenes India has a longitudinal extent of 30 degree so there is a time difference of 2 hours between Arunachal Pradesh and Gujarat but the watches are set for all parts of country according to the Indian Standard Time measured it is 2 and half degree longitude this is the reason why the watches so the same time everywhere in the India

 Arunachal Pradesh is the easternmost state and Gujarat is the westernmost state. Naturally, they experience such variation in the local time because of the longitudinal distance of 30° longitudes. This longitudinal distance of 30° longitudes makes a difference of 2 hours between the Arunachal Pradesh and the Gujarat. (1 degree = 4 minutes,30 degree = 4 {tex}\times{/tex} 30 = 120 minutes i.e 2 hours).

Hence, when it is 6 a.m. in Arunachal Pradesh, the local time at Gujarat is supposed to be behind by 2 hours as compared to the Arunachal Pradesh,it is 4 a.m. Therefore, it is correct to say that when the sun has already risen in the Arunachal Pradesh, it is still night in the Gujarat.

EVOLUTION OF THE EARTH

1. The earth was initially barren rocky and hot Object
2. Hydrogen and helium were present
3. It was formed about 4.6 by a the earth was Layered structure
4. Lighter layer is formed at the outer surface
5. Density increase to wards inside the core

Physical geography includes the study of lithosphere (landforms, drainage, relief and physiography), atmosphere (its composition,structure, elements and controls of weather and climate; temperature, pressure, winds,precipitation, climatic types, etc.),hydrosphere(oceans, seas, lakes and associated features with water realm) and biosphere ( life forms including human being and macro-organism and their sustaining mechanism, viz. food chain, ecological parameters and ecological balance).

The study of physical geography is emerging as a discipline of evaluating and managing natural resources. In order to achieve this objective, it is essential to understand the intricate relationship between physical environment and human beings. Physical environment provides resources, and human beings utilise these resources and ensure their economic and cultural development. Accelerated pace of resource utilisation with the help of modern technology has created ecological imbalance in the world. Hence, a better understanding of physical environment is absolutely essential for sustainable development.

1. The actual distance measured from east to west is only 2933 kilometer while the distance from north to south is 3,214 kilometer. 
2. This difference is based on the fact that the distance between two longitudes decreases towards the poles whereas the distance between two latitudes remains the same everywhere.

Dualism in geography is the differing belief of geographers over any geographical topic.

It is of two types-

1) Environmental determinism-It is the study of how the physical environment predisposes societies and states towards particular development trajectories. Nineteenth century approaches held that climate and terrain largely determined human activity and psychology, and it was associated with institutionalized racism.

2) Social determinism-It is the theory that social interactions and constructs alone determine individual behavior (as opposed to biological or objective factors). A social determinist would look only at social phenomena, such as customs and expectations, education, and interpersonal interactions, to decide whether or not a given person would exhibit any of these behaviors.

Dulism means contrasting and different views on a Geographical theme while dichotomy means distinct and separate streams of Geographical knowledge, however both had been very helpful in development and advancement of Geography as a discipline.

Physical geography is one of the two major sub-fields of geography. Physical geography is the branch of natural science which deals with the study of processes and patterns in the natural environment.