AQA · Physics · 8463
GCSE Physics: Transformers
Magnetism and electromagnetism · AQA GCSE Physics (8463), specification point 4.7.3.4. Cards are generated from the exam board's own specification for "Transformers", and every card links back to the page it came from. Higher tier only. Separate science only. Specification © AQA — used with attribution.
11 flashcards · Free to study · No account needed
Study this deck
Preparing your cards…
All questions and answers
Read through the full deck, or practise recalling each answer above.
What are the three components of a basic transformer?
Show answer
A primary coil and a secondary coil, both wound on an iron core.
Why is iron used for the core of a transformer?
Show answer
Because iron is easily magnetised.
What is the transformer equation linking potential differences and number of turns?
Show answer
Vp / Vs = np / ns — the ratio of primary to secondary p.d. equals the ratio of turns on the primary to turns on the secondary.
In a step-up transformer the secondary p.d. is ? than the primary p.d.
Show answer
greater
In a step-down transformer the secondary p.d. is ? than the primary p.d.
Show answer
less
What equation relates power input and output for a 100% efficient transformer?
Show answer
Vs × Is = Vp × Ip — power output at the secondary equals power input at the primary.
In a transformer, which coil does Vs × Is give the power of?
Show answer
The secondary coil — it is the electrical power output.
How does a transformer transfer energy from the primary coil to the secondary coil?
Show answer
The alternating current in the primary coil produces a changing magnetic field in the iron core, which induces a potential difference (and current) in the secondary coil.
Why must a transformer be supplied with alternating current rather than direct current?
Show answer
Only a changing (alternating) current produces the changing magnetic field needed to induce a p.d. in the secondary coil; a steady d.c. would induce nothing.
For a 100% efficient transformer, how is the input current Ip calculated from a required output power?
Show answer
Ip = (Vs × Is) / Vp — divide the output power by the primary p.d.
Why is electrical power transmitted at high potential differences?
Show answer
For the same power, a higher p.d. means a smaller current, so less energy is wasted heating the transmission cables.
Want to create your own cards? Create a free account. AI generation uses credits.