Which of the following statements are true about acceleration due to gravity

Options

A. g' is zero at the centre of earth
B. g' decreases if earth stops rotating on its axis
C. g' decreases in moving away from centre if `r gt R`
D. g' decrease in moving away from centre if `r lt R`

Answer

A, C

Explanation

Inside the earth
`g' = g (1 - (d)/(R )) = g ((R - d)/(R )) = (gr)/(R )`
where `r` is the distance from the centre of earth.
`g` increase when `r` increase provided `r lt R`
At the centre of earth `r = 0, g' xx 0//R = 0`
outside the earth `g' = g (1 - (2h)/(R ))` as `h` increase g' decreases.