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Sources of Information (in Hindi)
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This lesson is about the sources of information required to determine the Interior of the earth.

Bhairavi Tidke
2nd year B. Tech. Student, Design head of Bombay technologist of ICT, dancer, painter, interested in research and like to help people...

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Very hard working for providing facts Mam, Many Many thanks to you
1. Interior of the Earth Sources of information Radius of earth nearly 6370 km. Most of the information is based on estimates and inferences Part of information obtained through direct and indirect evidences . .

2. Direct sources . Solid material- rocks on earth surface . The depth we so far we reached is of 12 km(Kola in arctic ocean) Volcanic eruption-magma is thrown on earth surface-difficult to ascertain the depth of such magma

3. EXPLORING INSIDE EARTH Geologists have used two main types of evidence to learn about Earth's interior: direct evidence from rock samples and indirect evidence from seismic waves

4. Indirect sources Meteors that hits the earth. Gravitation, magnetic field and seismic activity Gravitational force is greater near poles and less towards equator Gravity anomaly gives us info. About distribution of mass Magnetic surveys-distribution of magnetic materials in that area . *

5. Gravitational Field Strenth: Inside the Earth i 8.5 mis 400 km A:Mohorovi i discontinuity B Core-mantle boundary (Gutenberg discontinuty) C: Lehmann discontinuity D Typical space shuttie orbt 9.8 m/s? 30-65 km 2 1 Coninental crust 2 Oceanic crust 3: Upper mantle 4 Lower mantie 5 Outer core 6 Inner core 2885 km 4 10.7 m/s 2270 km 5 61216 km B) 0.0 m/s 0 35 700 2885 5155 6371 km

6. Variation of g due to latitude g, = g-Ruy2 cos2 W rounds/sec NP As latitude il increases, cos decreases, so g' will increase : The value of g, increases as we v move from the equator to the pole due to rotation of the earth. Sp 67

7. a 6372 km c 6350 km G M 2 G M But, a > , therefore,