Summary and Exam Tips for Electricity – Electric current
Electricity – Electric current is a subtopic of Physics, which falls under the subject Science in the Edexcel Lower Secondary curriculum. Electricity is a versatile form of energy that can be converted into other forms. It primarily originates from two sources: power stations, which provide substantial electricity for various appliances, and electric cells (batteries), which offer a smaller, portable, and safe supply. An electric current is the flow of electricity necessary for operating electrical devices, moving along a path known as an electric circuit.
Electric charges consist of positive charges (protons) and negative charges (electrons). When these charges flow in a circuit, they create a current. For instance, a battery energizes electrons, pushing them from the negative to the positive terminal. Electrons, being negatively charged, can cause an object to gain a negative charge if they accumulate, or a positive charge if they are lost. Conductors allow charge flow, while insulators do not. Current is measured in amperes (A) using an ammeter, connected in series to the circuit. Small currents are measured in milliamps (mA), where .
Exam Tips
- Understand the difference between conductors and insulators. Remember that metals and graphite are conductors, while plastics and glass are insulators.
- Be familiar with how an ammeter is used to measure current and its placement in a circuit.
- Practice explaining how a battery works in a circuit, focusing on the flow of electrons from the negative to the positive terminal.
- Memorize the conversion between amperes and milliamps: .
- Review the concept of electric charge and how gaining or losing electrons affects an object's charge.
