Charge Charge Types of Gauss’s surfaces Surface area for Gauss’s Electric distribution density which theorem field Intensity Infinitely Linear Cylindrical Lateral surface long charge area straight density uniformly charged conductor Infinitely Surface extended charge Plane plane sheet density Plane surface of = Charge uniformly Charged Surface spherical charge shell density Spherical surface Properties of electric field lines:. 1.The imaginary path along which a unit positive charge placed in the electric field tends to follow is the magnetic line of force 2. The electric lines of force emanate from a positive charge and terminate on a negative charge. The tangent to an electric field line at any point gives the direction of the electric field at that point. 3. No two electric lines of force cross each other. If they do, then at the point of intersection, there will be two tangents. It means there are two values of the electric field at that point, which is not possible. 6. Electric lines of force are closer (crowded) where the electric field is stronger and the lines spread out where the electric field is weaker. 4. Electric lines of force contract lengthwise to represent attraction between two unlike charges and Electric lines of force exert lateral (sideways) pressure to represent repulsion between two like charges. Electrostatic Potential: Work done per unit positive Test charge to move it from infinity to that point in an electric field against the field direction . It is a scalar. SI unit: J/C or V V = W / qo Electric potential at any point at a distance r from a point charge q: Graphs: Variation of E & V due to a point charge at any point in the field with r (Graph-1) and Variation of V with 1/r (Graph-2)
Charge distribution Charge density Types of Gauss’s surfaces Surface area for which Gauss’s theorem Electric field Intensity Infinitely long straight uniformly charged conductor Linear charge density Cylindrical Lateral surface area Infinitely extended plane sheet of Charge Surface charge density Plane Plane surface = uniformly Charged spherical shell Surface charge density Spherical surface Properties of electric field lines:. 1.The imaginary path along which a unit positive charge placed in the electric field tends to follow is the magnetic line of force 2. The electric lines of force emanate from a positive charge and terminate on a negative charge. The tangent to an electric field line at any point gives the direction of the electric field at that point. 3. No two electric lines of force cross each other. If they do, then at the point of intersection, there will be two tangents. It means there are two values of the electric field at that point, which is not possible. 6. Electric lines of force are closer (crowded) where the electric field is stronger and the lines spread out where the electric field is weaker. 4. Electric lines of force contract lengthwise to represent attraction between two unlike charges and Electric lines of force exert lateral (sideways) pressure to represent repulsion between two like charges. Electrostatic Potential: Work done per unit positive Test charge to move it from infinity to that point in an electric field against the field direction . It is a scalar. SI unit: J/C or V V = W / qo Electric potential at any point at a distance r from a point charge q: Graphs: Variation of E & V due to a point charge at any point in the field with r (Graph-1) and Variation of V with 1/r (Graph-2)
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