A dielectric sphere is a solid object made of an insulating material that has the ability to store electric charges. This material, known as a dielectric, does not allow the flow of electrons through it, which makes it a good medium for storing charges.
In a dielectric sphere, free charges are evenly distributed throughout the volume of the sphere. This means that the charges are not concentrated at a specific point, but rather spread out in a uniform manner.
When placed in an external electric field, a dielectric sphere will polarize, meaning that the charges within the sphere will align in a specific direction, creating an internal electric field that opposes the external field. This results in a decrease in the overall electric field within the sphere.
The presence of a dielectric sphere between the plates of a capacitor increases the capacitance of the system. This is because the dielectric material reduces the electric field between the plates, allowing for more charge to be stored at a lower potential difference.
The magnitude of free charges in a dielectric sphere is affected by the permittivity of the dielectric material, the size of the sphere, and the strength of the external electric field. The higher the permittivity and the larger the sphere, the greater the magnitude of free charges will be. Conversely, a weaker external field will result in a lower magnitude of free charges.