The formula for finding the electric field inside a sphere is E = (Qr)/(4πε0r3) where E is the electric field, Q is the charge of the sphere, r is the distance from the center of the sphere, and ε0 is the permittivity of free space.
The direction of the electric field inside a sphere is always radial, pointing towards the center of the sphere. This means that the electric field lines will be directed from the surface towards the center of the sphere.
No, the electric field inside a sphere can never be zero. This is because the electric field is directly proportional to the charge of the sphere, and as long as the sphere has a non-zero charge, there will always be an electric field inside the sphere.
In a conducting sphere, the electric field inside the sphere is zero. This is because the charges in a conducting material are free to move and will distribute themselves in such a way that the electric field inside the sphere is canceled out. In an insulating sphere, however, the electric field inside the sphere will follow the formula mentioned in the first question.
Yes, the electric field inside a sphere can be negative if the charge of the sphere is negative. The direction of the electric field will still be pointing towards the center of the sphere, but the negative sign in the formula will result in a negative value for the electric field.