Question

In deriving the formula for the gravitational field due to a solid sphere at a point on the axis of the sphere, the sphere is assumed to be made up of

• A. thin concentric discs of equal width and radius
• B. uniform density
• C. thin concentric discs of increasing width and and increasing radius
• D. thin concentric discs of increasing width and and equal radius

Answer 1

The correct option is B uniform density

For deriving the expression for gravitational field, it is assumed that density of the sphere is same through out the sphere in all directions and hence a uniform mass density is used to find the mass of a concentric sphere
The correct option is (b)