# Electricity Generation, Transmission & Efficiency Guide
> Learn how electricity is generated, transmitted through the National Grid, and optimized for efficiency using Ohm's Law and transformers.

Tags: electricity, physics, national-grid, renewable-energy, transformers, ohms-law, power-generation
## Electricity: Generation, Transmission & Efficiency
- Overview of AC/DC, energy sources, and grid efficiency.
- Aligned with BTEC Level 3 Applied Science criteria.

## How a Generator Produces AC Electricity
- Electromagnetic induction: a coil spins between magnets to move electrons.
- Ways to increase voltage: more wire turns, stronger magnets, faster spinning, larger coil, or iron core.

## Wind Turbines and Solar Cells
- **Wind Turbines:** Wind turns rotor blades connected to a gearbox and AC generator.
- **Solar (PV) Cells:** Light knocks electrons loose in silicon crystals to create DC electricity.

## Batteries: Zinc-Carbon and Rechargeable
- **Zinc-Carbon:** Non-rechargeable chemical reaction (DC).
- **Rechargeable:** Lithium-Ion and Lead-Acid batteries use reversible chemical reactions.

## Ohm's Law
- Calculation formula: V = IR (Voltage = Current × Resistance).
- Essential for investigating circuit resistance.

## The National Grid and Efficiency
- Path: Power Station (25kV) → Step-Up Transformer (400kV) → Transmission Lines → Step-Down Transformer → Home (240V).
- High voltage reduces current and minimizes energy lost as heat (I"R losses).

## Environmental Impacts
- Comparison of renewables (Wind, Hydro) vs. non-renewables (Fossil Fuels, Nuclear).
- Highlights issues like CO₂ emissions, radioactive waste, and habitat destruction.
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