Important revision notes of Class 12 Physics, Chapter 2 - Electrostatics Potential and Capacitance (based on NCERT books) are available in this article. These notes are helpful for revision purpose and important for CBSE Class 12 board examinations.

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Where, r is the magnitude of the position vector of the point and q is the source charge.

CBSE Class 12th Physics Notes: Current Electricity

Electric Potential at a point due to ‘n’ number of Point Charges:


Electric potential due to a group of charges at a given point is the algebraic sum of the potentials due to individual charges

Electric Potential at a point due to an Electric dipole:

The electric potential at a point due to an electric dipole is given by the relation:

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CBSE Class 12th Physics Notes: Ray Optics & Optical Instruments

Equipotential Surfaces:

It is the surface at every point of which electric potential remain same.

There will be no work done in moving the test charge from one point of equipotential surface to the other.

Equipotential surface through a point is always normal to the electric field at that point.

Electrostatic Potential Energy due to a system of Charges:

It is the total amount of work done by an external agent in bringing them from infinity to the present arrangement in the system.

Electrostatic potential energy for a system of two charges q1 and q2 at a separation r is given by

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Electric Flux

It is defined as the total number of electric filed lines of force passing through the area normally.

Mathematically,

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CBSE Class 12th Physics Notes: Wave Optics

Gauss’s Theorem:

The electric flux through any closed surface is equal to 1/ εo times the total charge enclosed by the surface.

Mathematically,

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Where symbols have their respective meaning.

Electric Field Intensity Due to a Uniformly Charged Spherical Shell:

At any point outside the surface of the uniformly charged spherical shell

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Where, E is electric field, q is total charge on the sphere, r is the distance of the point from the centre of sphere.

At any point on the surface of the uniformly charged spherical shell

The electric field on the surface of the uniformly charged spherical shell is maximum and given by,

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At any point inside the uniformly charged spherical shell

Inside the shell, charge (q) = 0, so, E = 0.

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CBSE Class 12th Physics Notes: Electric Charges and Fields

Electric Field Intensity Due to a Non-Conducting Charged Solid Sphere:

At any point inside the surface of the sphere

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Here, q is the total charge on the sphere, r is the radius of the Gaussian surface and R is the radius of the sphere.