P6

• Electric field


  Defined as the force per unit charge at a given point
• Michael Faraday, an English scientist, introduced the concepts of fields and lines of force which paved the way to several important discoveries in physics
• Results of Michael Faraday’s experiments revealed that the direction of the force in a given electric field may be represented as field lines going in and coming out of negative and positive charges, respectively
• Electric flux


  Refers to the “rate of the flow of the electric field,” as determined by the number of electric field or flux lines passing through a given region
• Electric flux is the property of an electric field relating to the measure of its strength
• Electric field lines


  Always emerge from a positive charge and end at a negative charge
• Electric flux may be inward or outward, depending on the direction of the electric field vectors
• A positive charge within a region will have an outward electric flux passing through its surface
• A negative charge will have an inward electric flux through its surface
• A region containing a zero charge has “no net electric flux” passing outward or inward
• The net electric flux going outward the surface of the region is directly proportional to the magnitude of the net charge enclosed by that region
• In the case of uniform electric fields, the electric flux can be calculated
• Electric flux is directly proportional to the number of electric field lines passing through a surface area
• Electric flux is calculated differently when the surface area and electric field are perpendicular, at an angle, or parallel
• Electric flux passing through a square region with a uniform electric field of 9000 N/C and an area of 25 m^2 is 2.25 x 10^6 Nm^2/C
• Electric flux contained in a uniform electric field of 3500 N/C parallel to a square surface with an area of 49 m^2
• Electric flux passing through a rectangle with sides of 13 m and 25 m found in a region with a uniform electric field of 200 N/C and an angle of 55º with respect to the horizontal
• Electric flux refers to the “rate of the flow of the electric field.”
• There is no electric flux present when the electric field is perpendicular to the surface.
• The magnitude of the net charge enclosed in a given region is inversely proportional to the net electric flux going outward the surface.
• The net electric flux going outward the surface of the region is directly proportional to the magnitude of the net charge enclosed by that region.
• A positive charge within a region will have an outward electric flux passing through its surface, whereas a negative charge will have an inward electric flux traversing its surface. A zero charge contains no electric flux.
• If a point charge is situated at the very center of a solid cube, the amount of flux passing through each of the faces of the cube is unknown.
• Electric Flux when A and E Are Parallel: φE = E * A
• Electric Flux when A and E Are at an Angle: φE = E * A * cos(θ)
• Electric flux passing through a rectangle with sides of 13 m and 25 m found in a region with a uniform electric field of 200 N/C and an angle of 55º with respect to the horizontal is 3.73 x 10^4 Nm^2/C.
• Electric flux traversing a rectangle with a surface area of 90 m^2, a uniform electric field of 135 N/C, and an angle of 85º from the horizontal needs to be calculated.
• A disk with a radius of 0.5 centimeters and tilted at an angle of 45º with respect to the horizontal experiences an electric flux of 7.50 x 10^-3 Nm^2/C. The uniform electric field of the disk is 135 N/C.
• The value of the electric field in a disk with a radius of 12 cm and tilted at an angle of 63º, with an electric flux of 13.76 Nm^2/C passing through the area, needs to be determined.
• One may visualize circuitry as an energy conversion system
• In an electric circuit, the chemical energy from a battery does work on a charge by moving it from low to high potential terminal
• This is then transformed into electrical energy within the battery, before being transformed into other forms of energy, such as heat and light
• This lesson will enable you to probe deeper into how electric potential enables this mechanism to work
• What is electric potential?
• Relate the electric potential with work, potential energy, and electric field
• Solve problems involving electric potentials in contexts such as, but not limited to, electron guns in CRT TV picture tubes, conditions for merging of charge liquid drops
• Differentiate between electric potential and potential difference
• Explain the relationships between charges, electric field, and electric potential
• Calculate the electric potential in a unit of charge
• Identify the applications of electric potential and potential difference in circuitry