Question

what is variation in value of g

Answer 1

Its value is 9.8 m/s2 on Earth. That is to say, the acceleration of gravity on the surface of the earth at sea level is 9.8 m/s2. When discussing the acceleration of gravity, it was mentioned that the value of g is dependent upon location. There are slight variations in the value of g about earth's surface.

Answer 2

The value of g = 9.8m/s^2
g at the centre of the earth is 0 as r=0
g decreases as we move away from the surface of the earth
The value of g is maximum on the earth’s surface.
The g at poles is larger as compared to g at the equator since distance between pole and centre of earth is less than the distance between equator and centre of earth.
It is so because g is inversely proportional to the square of radius of earth.
Hope this helps...