Physics Notes
Variation of Electrostatic Field Intensity
Uniformly Charged Conductive Sphere (Hollow/Solid)
The electrostatic field intensity of a uniformly charged conductive sphere varies as follows:
• Inside a Hollow Sphere: The electrostatic field intensity is zero at all points
inside the sphere.
• Inside a Solid Sphere: The electrostatic field intensity increases linearly with
distance from the center up to the surface.
• Outside the Sphere: The field intensity decreases with the square of the distance
from the center, following the inverse-square law.
Uniformly Charged Non-Conductive Solid Sphere
For a uniformly charged non-conductive solid sphere, the variation of the electrostatic
field intensity is:
• Inside the Sphere: The field intensity increases linearly with distance from the
center.
• Outside the Sphere: The field intensity decreases with the square of the distance
from the center, similar to a point charge.
Uniformly Charged Rod
The electrostatic field intensity of a uniformly charged rod varies as:
• Along the Axis Perpendicular to the Rod: The field intensity decreases inversely with distance from the rod.
• At Points Along the Length of the Rod: The field intensity varies depending
on the specific location relative to the rod’s ends and its central axis.
Uniformly Charged Conductive Plate
For a uniformly charged conductive plate, the variation of the electrostatic field intensity
is:
• On Either Side of the Plate: The field intensity is constant and does not vary
with distance from the plate.
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Uniformly Charged Non-Conductive Sheet with Negligible Thickness
In the case of a uniformly charged non-conductive sheet with negligible thickness:
• On Either Side of the Sheet: The electrostatic field intensity is constant and
equal on both sides, similar to a conductive plate but without the presence of freemoving charges.
Distribution of Electrostatic Field Between Two Identical Charged
Conductive Plates
When two identical charged conductive plates are brought close to each other:
• Between the Plates: The electrostatic field is uniform and directed perpendicular
to the surfaces of the plates, with field lines running from the positively charged
plate to the negatively charged plate.
• Outside the Plates: The electrostatic field is minimal due to the cancellation of
fields from the opposite charges on each plate.
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