Electric charge is create when electrons move within, leave, or enter an object. A normal atom has a equal number of protons and electrons, so it has no net charge. However, if an atom loses an electron it becomes negatively charged and positively charged if it gains an electron. The charge of each electron is -1.6•10^-19 Coulombs. Called the elementary charge, this is the smallest charge any object can have.
Two objects with opposite charges will attract each other while two objects with the same charge will repel each other. The force between these two objects is determined by Coulomb's Law:
Two objects with opposite charges will attract each other while two objects with the same charge will repel each other. The force between these two objects is determined by Coulomb's Law:
Where k is 9.0•10^9 Nm^2/C^2
Because there is a force between two charged objects, moving these objects relative to each other requires work. Similar to gravitational potential energy, the work done to the object becomes stored as electric potential energy. The equation electric potential energy is similar to Coulomb's Law, as the work done to move an object is the product of the electric force and distance traveled.
https://www.youtube.com/watch?v=Yvuo0IQuW64
A circuit is created when current flows in a loop. To move electrons, the circuit must have some electric potential difference, often coming from a battery or generator. This part of the circuit is called the electromotive force. This force (while not an actual force) can be used to do work in a circuit.
Resistors are components in a circuit that resist electrical flow. Resistors draw power from a circuit which can calculate by Ohm's law: Voltage (V) = Current (I) • Resistance (R). For example, a resistor with a lower resistance draws more current and therefore more power (which can be measures as Volt•Amps). The resistance of a resistor can be calculated based on the shape and material properties of the resistor component itself. The resistance of a resistor is proportional to its resistivity, the material property to resist electrical flow, and its length. However, resistance is inversely proportional to the cross-sectional surface area of the resistor.
How multiple resistors are arranged in a circuit impacts its total resistance. The resistance of resistors placed in series adds as this is essentially increasing the length of the resistor. The resistance decreases of multiple resistors are placed in parallel as the total resistance in a parallel circuit will be the inverse of the sum of the inverse of each resistor. This is because adding resistors in parallel is effectively increasing a single resistor's cross-sectional surface area.
https://www.youtube.com/watch?v=-w-VTw0tQlE
The exact voltage and current flowing through each part of a circuit can be calculated using Kirchhoff's rules. Kirchhoff's Loop Rule states that all the voltages in a series circuit will add to zero. For example, two resistors with the same resistance connected in series to a 6 volt battery will each have a voltage of 3 volts across them.
Kirchhoff's Junction Rule states that the current going into a junction will be the same as the current leaving the junction. This rule is base off of the conservation of charge.
https://www.youtube.com/watch?v=C1NVOLf4gnc
Widget is not loading comments...