A solid sphere of radius R and mass density `rho` is surrounded by another outer sphere of density `2 rho`. Let `E_(P)` is gravitational field at P and `E_(Q)` is at Q. If the ratio of `E_(Q)//E_(P)=3k//4`. Find the value of k.

Two uniform solid spheres of same materical and same radius are touching each other density is 'rho' then find out gravitational force between them .

A system consits of a uniformly charged sphere of radius R and a surrounding medium filled by a charge with the volume density rho=alpha/r , where alpha is a positive constant and r is the distance from the centre of the sphere. Find the charge of the sphere for which the electric field intensity E outside the sphere is independent of R.

Consider a solid sphere oF radius R and mass density rho(r)=rho_(0)(1-(r^(2))/(R^(2))) 0 lt r le R . The minimum density oF a liquid in which it will Float is:

A solid sphere having radius R and uniform charge density rho has a cavity of radius R/2 as shown in figure.Find the value of |E_A /E_B|

A solid sphere of radius R has a charge Q distributed in its volume with a charge density rho=kr^a , where k and a are constants and r is the distance from its centre. If the electric field at r=(R)/(2) is 1/8 times that r=R , find the value of a.

For an infinitely long solid cylinder of radius R having a uniform density , the gravitational field at a distance r_(1) is E_(1) and at a distance r_(2) is E_(2) , then

The acceleration due to gravity g and density of the earth rho are related by which of the following relations? (where G is the gravitational constant and R_(E) is the radius of the earth)

Mass density of sphere having radius R varies as rho = rho_0(1-r^2/R^2) . Find maxium magnitude of gravitational field

The density inside a solid sphere of radius a is given by rho=rho_0/r , where rho_0 is the density at the surface and r denotes the distance from the centre. Find the gravitational field due to this sphere at a distance 2a from its centre.

A cavity of radius r is present inside a fixed solid dielectric sphere of radius R, having a volume charge density of rho . The distance between the centres of the sphere and the cavity is a. An electron is released inside the cavity at an angle theta = 450 as shown. The electron (of mass m and charge –e) will take ((Psqrt(2)mrepsilon_(0))/(earho))^(1//2) time to touc the sphere again. Neglect gravity. find the value of P: