Gravitation - Result Question 21

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21. Assuming earth to be a sphere of uniform density, what is the value of ’ $g$ ’ in a mine 100 $km$ below the earth’s surface? (Given, $R=6400$ $km$ )

======= ####21. Assuming earth to be a sphere of uniform density, what is the value of ’ $g$ ’ in a mine 100 $km$ below the earth’s surface? (Given, $R=6400$ $km$ )

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/gravitation/gravitation—result-question-21.md (a) $9.65 m / s^{2}$

(b) $7.65 m / s^{2}$

(c) $5.06 m / s^{2}$

(d) $3.10 m / s^{2}$

[2001]

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Answer:

Correct Answer: 21. (a)

Solution:

  1. (a) We know that effective gravity $g^{\prime}$ at depth below earth surface is given by

$g^{\prime}=g(1-\frac{d}{R})$

Here, $d=100 km, R=6400 km$,

$\therefore \quad g^{\prime}=9.8(1-\frac{100}{6400})=9.65 m / s^{2}$