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.

It will be decided by your subject teacher.

“Pollution” is the mixing/blending of foreign or unwanted agents into some element or compound, which thereby, reduces its quality, by causing “Degradation”. “Pollution” and “Degradation” are directly proportional to each other. The more the pollution, the more the degradation.

For example, mixing waste products with water and smoke with air causes water pollution and air pollution, respectively. This pollution lowers the quality of water for consumption and air for respiration, thus causing water pollution and air pollution, respectively. Thus, more pollution means more degradation.

Physical geography is that branch of natural science which deals with the study of processes and patterns in the natural environment like the atmosphere, hydrosphere, biosphere, and geosphere, as opposed to the cultural or built environment, the domain of human geography.

Areas of physical geography include:

• Geomorphology: the shape of the Earth’s surface and how it came about
• Hydrology: the Earth’s water
• Glaciology: glaciers and ice sheets
• Biogeography: species, how they are distributed and why
• Climatology: the climate
• Pedology: soils
• Palaeogeography: how the continents have moved over time
• Coastal geography: how the ocean and land affect each other
• Oceanography: the oceans and seas
• Quaternary science: the geography of the last 2.6 million years, including the last ice age
• Landscape ecology: how the landscape affects things like the distribution of plants and animals
• Geomatics: gathering, storing and processing geographic information – for example, making maps