Graphical variation of electric field due to a uniformly charged insulating solid sphere of radius R, with distance r from the centre O is represented by:

The electric field due to a uniformly charged insulating solid sphere varies with distance r from the centre O in the following way:

1. Inside the sphere (r<R): The electric field increases linearly with distance from the center. This is because as you move further into the sphere, there is more charge enclosed within your radius, leading to a stronger electric field. The electric field E can be represented by the equation E = kQr/R^3, where k is Coulomb's constant, Q is the total charge of the sphere, r is the distance from the center, and R is the radius of the sphere.

2. On the surface of the sphere (r=R): The electric field reaches its maximum value. This is because all the charge of the sphere is enclosed within your radius. The electric field E can be represented by the equation E = kQ/R^2.

3. Outside the sphere (r>R): The electric field decreases with the square of the distance from the center. This is because the sphere behaves as a point charge when you are outside of it, and the electric field of a point charge decreases with the square of the distance. The electric field E can be represented by the equation E = kQ/r^2.

So, if you were to graph the electric field as a function of distance from the center, it would increase linearly from zero at the center to a maximum at the surface of the sphere, then decrease as 1/r^2 for r>R.