Common Misconceptions
Part of National Grid & Transformers — GCSE Physics
This common misconceptions covers Common Misconceptions within National Grid & Transformers for GCSE Physics. Revise National Grid & Transformers in Extra Topics for GCSE Physics with 13 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 12 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 12
Practice
13 questions
Recall
12 flashcards
⚠️ Common Misconceptions
Misconception 1: "Transformers work with DC as well as AC"
Transformers only work with alternating current. A DC supply creates a steady (constant) magnetic field. A constant magnetic field does not induce a voltage in the secondary coil — you need a changing field for induction. AC constantly reverses direction, so its magnetic field constantly changes, enabling induction.
Misconception 2: "High voltage is dangerous, so why does the Grid use it?"
High voltage is indeed dangerous for direct human use — that's why it's stepped down before reaching homes. But for transmission, the risk is managed by using insulated cables on very tall pylons. The engineering benefit (massively reduced power loss) greatly outweighs the risk, which is mitigated by appropriate safety measures.
Misconception 3: "The transformer creates extra power"
Transformers cannot create energy. If voltage is doubled, current is halved. Power (V × I) stays the same (in an ideal transformer). A real transformer is slightly less than 100% efficient, losing a small amount of energy as heat in the iron core and coils.
Misconception 4: "The step-up transformer is at the home end"
It's the opposite. Step-up transformers are at the power station end, to increase voltage for transmission. Step-down transformers are at the substation end (closer to homes) to reduce voltage back to safe levels.