Electricity: Charge, Voltage and Energy Change

Charge: This is an intrinsic property of particles at a subatomic level. The vast majority of objects are neutral because they contain equal numbers of positive (protons) and negative (electrons) charges. An imbalance of charges can lead to electricity.
Positive and Negative Charge: Protons carry a positive charge and electrons carry a negative charge. When a material loses electrons, it becomes positively charged and when it gains electrons, it becomes negatively charged.
Unit of Charge: The unit of electrical charge is the coulomb (C). It’s an extremely large charge. A single electron has a charge of approximately -1.6 x 10^-19 C.
Voltage: Voltage or electric potential difference is defined as the energy per unit charge. In other words, it’s the amount of energy transferred from an energy source when one unit of positive charge moves through a complete electrical circuit.
Voltage and Energy Transfer: High voltage indicates a large energy transfer per unit charge, while a low voltage indicates a smaller energy transfer per unit charge.
Unit of Voltage: The SI unit of voltage is the Volt (V). One Volt corresponds to one joule of energy per coulomb of charge.
Energy Change in Electrical Circuits: Energy transforms from one form to another as electric charges move through the circuit. When you switch on a light, electrical energy changes into light and heat energy. In a loudspeaker, electrical energy changes into kinetic energy and then into sound energy.
Conservation of Energy: In any electrical circuit, the total energy input must always equal the total energy output due to the law of conservation of energy.
Ohm’s Law: This law states that the current passing through a conductor between two points is directly proportional to the voltage across the two points, and it’s expressed as V=I*R where, V is the voltage, I is the current and R is the resistance.
Electric Potential Energy: This is the energy a charged object possesses because of its position relative to other charged objects. It’s directly proportional to the quantity of charge and increases with increasing distance from the other charge.

Remember, studying the fundamental concepts can greatly help in understanding the topics. Consider practical applications and everyday examples to improve retention of these concepts. Always practise problems pertaining to Charge, Voltage and Energy Change to enhance problem-solving skills.