[PHY] Chapter 17 - Current Electricity

DARRELL ER (COPYRIGHTED) © TOPIC 17: CURRENT ELECTRICITY DARRELL ER (COPYRIGHTED) ©

CHAPTER ANALYSIS THE ABOUT TIME EXAM WEIGHTAGE DARRELL ER (COPYRIGHTED) ©

CURRENT CHARGE / TIME CONVENTIONAL CURRENT & ELECTRON FLOW KEY CONCEPT DARRELL ER (COPYRIGHTED) ©

visualising electricity CHARGE CURRENT VOLTAGE DARRELL ER (COPYRIGHTED) ©

PIKACHU RACE VISUALISATION This is a story about a pikachu participating in a race. He has to run one full lap around the circuit. He starts off at the Pokemon center with full health. However, along the way, he come across Team Rocket. Although Team Rocket offered some resistance, Pikachu was still able to defeat them as usual. He uses all his energy and thunderbolt the shit out of them. Now he is out of energy but with nothing left in his way, he makes his way safely back to the Pokemon center and replenishes his energy back to full health. Pikachu is ready to go again! DARRELL ER (COPYRIGHTED) ©

COMPLETE CIRCUIT VISUALISATION This is how electricity works! Pikachu is the charge, a particle capable of carrying electrical energy, that moves around the circuit. Pokemon center is the source (battery), where the charge replenishes its electrical energy after going one round around the complete circuit. In the battery, chemical potential energy is converted to electrical energy which is supplied to the charge. Team Rocket is the component (light bulb). In order to overcome it, the charge has to use its electrical energy. After the charge hands over the required electrical energy, it is then allowed to pass through. In the light bulb, electricity energy received from the charge is converted to light and heat energy. charge component battery DARRELL ER (COPYRIGHTED) ©

CURRENT VISUALISATION SO WHAT IS CURRENT? Current is defined as the rate of flow of electrical charges. In order words, the amount of charges flowing in the circuit per second. VISUALISATION The whole process of pikachu going around the circuit is really quick, in milliseconds. Furthermore, multiple pikachus can be released to go around the circuit at the same time. Current measures the number of pikachus going around the circuit every second! Another analogy is ERP. The amount of cars passing through the ERP per second, is the rate of flow of cars. Current is the rate of flow of charges! charge component battery DARRELL ER (COPYRIGHTED) ©

DEFINITION Current is defined as the rate of flow of electrical charges. Unit: Ampere (A) Formula: Current is measured with an ammeter (which has very low internal resistance). The low resistance is to ensure that the ammeter does not affect the current flow. It must be connected in series so that electric current flow through the ammeter, via the positive terminal and leave via the negative terminal. (It’s like a