Two homogeneous spheres `A and B` of masses `m and 2 m` having radii `2 a` and `a` respectively are placed in contact. The ratio of distance of c.m from first sphere to the distance of c.m from second sphere is :

Two homogeneous spheres A and B of masses m and 2m having radii 2a and a respectively are placed in touch . The distance of the centre of mass from the first sphere is

Two homogeneous spheres A and B of masses m and 2m having radii 2a and a respectively are placed in touch . The distance of the centre of mass from the first sphere is

Two homogeneous spheres P and Q of different materials and masses 1 kg and 2 kg are kept in contact. The radii of A and B are 20 cm and 10 cm respectively. What is the distance of their centre of mass from the centre of A?

Two spheres A and B of radii 17 cm each and having charges of 1 and 2 coulombs respectively are separated by a distance of SO cm. The electric field at a point on the line joining the centres of two spheres is approximately zero at some distance from the sphere A. The electric potential at this point is:

Two spheres of the same material have radii 1m and 4m and temperatures 4000K,respectively. The ratio of the energy radiated per second by the first sphere to that by the second is

Two spheres of same material have radii 1 m and 4 m and temperatures 4000 K and 2000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is

Two spheres of the same material have radii 1m and 4m and temperatures 4000K and 2000K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is