This definitions covers Key Terms within National Grid & Transformers for GCSE Physics. Revise National Grid & Transformers in Extra Topics for GCSE Physics with 14 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Terms
- National Grid
- The network of cables, pylons, and transformers that distributes electrical power from power stations to homes, schools, and businesses across the country.
- Transformer
- A device that uses electromagnetic induction to change the voltage (and current) of an AC electrical supply, while keeping power approximately constant.
- Step-up transformer
- A transformer that increases voltage. Has more turns on the secondary coil than the primary coil. Used at power stations before transmission.
- Step-down transformer
- A transformer that decreases voltage. Has fewer turns on the secondary coil than the primary. Used at substations before supplying homes.
- Electromagnetic induction
- The production of a voltage (and current if in a closed circuit) when a conductor experiences a changing magnetic field.
- Turns ratio
- The ratio of turns on the primary coil to turns on the secondary coil, which equals the ratio of primary to secondary voltage.
Practice questions for National Grid & Transformers
What is the function of a step-up transformer in the National Grid?
Explain why electricity is transmitted at high voltage and low current through the National Grid power cables.
Quick recall flashcards
What voltage do homes receive?
230 V
How does a transformer work?
AC in primary creates changing magnetic field → iron core transfers field to secondary → changing field induces voltage in secondary (electromagnetic induction)