Resistance and Conductivity
Resistance opposes the flow of electrons through a material and is measured in ohms. For a given voltage, higher resistance results in less current flow. Several factors affect a wire's resistance: thinner wires have more resistance than thick ones, longer wires have more resistance than short ones, and hotter materials generally have greater resistance.
Resistors are components that deliberately convert electrical energy into other forms. Light bulbs transform electricity into light and some heat, while electric heaters convert electrical energy primarily to heat. These conversions happen because of the resistance in these devices.
Materials conduct electricity differently. Conductors like copper and silver allow electricity to flow easily, which is why copper is commonly used in electrical wiring. Insulators such as glass, rubber, and plastics have high resistance and block electrical flow, making them perfect for supporting and separating conductors.
🔍 Real-world connection: Your phone charger has insulated wires to prevent shocks and short circuits - the copper inside conducts electricity while the plastic coating insulates it!
Semiconductors occupy the middle ground between conductors and insulators. They can be modified by adding specific atoms to control their conductivity, which is why they're crucial in modern electronics. At extremely low temperatures below−196°C, certain metals and ceramics become superconductors with zero electrical resistance.