Electric Charges and Field

Force per unit area of a charged conductor: Let us consider the electric field E at any point P very near, but outside, the surface of a charged conductor is E = E1 + E2. Where E1 is the field due to the charge of small area ds around P, and E2 due to the […]

Solid angle: The projection of a area divided by r2 (position vector) is called solid angle. The solid angle subtended by an area at a point O is given by Ω = . Where  is the projection of area. For sphere the solid angle subtended at the centre is Ω =   =  = =

5. Oscillation of a charge: Two +q charge particles are placed at point A (0, a) and B (0, -a) on the Y axis and another charge particle –Q is released from rest at point C (b,0) on the X axis. At any instant -Q is at point D of distance x from origin. *(i)

1. Concept of electrostatic force: 1. Force on a point charge due to uniformly charged rod: A rod of length L is uniformly charged by Q placed at a distance D from a point charge q at P. Charge per unit length of the rod is λ = . We consider an elementary part of

Concept of conductor: 1. Electric field at the surface of a conductor: Let us consider an elementary surface ds of a conductor of surface charge density . The surface is enclosed by a cylindrical Gaussian surface which is inside and outside of the conductor. As the electric field is perpendicular to the surface so flux

Concept on electric field: 1. Field of two oppositely charged sheets: Two infinite plane sheets each of surface charge density σ and –σ are placed parallel to each other at a small distance d. Electric field for sheet 1 and 2 are E1 = E2 = . Feld at point A is   + 0

Electric flux: The electric flux through a surface inside an electric field is the total number of electric lines of force crossing the surface in a direction normal to the surface. If E is the electric field creates angle θ with surface of elementary area dS then electric flux, dɸE = EdScosθ Or, dɸE =

Electrostatic dipole: Electrostatic dipole consists of a pair of equal and opposite point charges separated by a very small distance. Example: H2O, NH3 etc.  Electrostatic dipole moment of an electric dipole is defined as the product of the magnitude of either charge of the dipole and the dipole length. If +q and –q are the

Electric field intensity of a uniformly charged infinitely long thin wire: Let us consider a long thin wire having uniformly positive linear charge density λ. We consider the elementary length dl of the wire carry small charge dq = λdl at a distance l from point O of the wire. The magnitude of the electric

Electric field intensity:  Electric field is a region of space around a charge or a system of charges which extends upto infinity within which other charged particles experience electrostatic force. The electric field strength or field intensity at a point in an electric field is the force acting on a test charge (unit positive charge)