Electromagnetic Induction and Generators Quiz
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5 questions, one answer each
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1. What is induced across a conductor when it moves relative to a magnetic field?
- A. A current only, never a potential difference
- B. A potential difference
- C. A permanent magnetic pole
- D. Nothing, unless the conductor is iron
2. Which type of generator uses slip rings to produce alternating current?
- A. A dynamo
- B. A transformer
- C. An alternator
- D. A relay
3. A transformer has 100 turns on the primary coil and 400 on the secondary coil, with 230 V applied to the primary. What is the secondary voltage?
- A. 57.5 V
- B. 230 V
- C. 460 V
- D. 920 V
4. Why is electrical power transmitted at high voltage in the National Grid?
- A. To increase the current and heat the cables faster
- B. To reduce the current, reducing energy losses in the cables
- C. Because transformers cannot work at low voltage
- D. To make the electricity safer for homes
5. Why does a transformer not work with direct current (dc)?
- A. Dc produces too strong a magnetic field
- B. Dc does not produce a changing magnetic field needed for induction
- C. Dc cannot flow through an iron core
- D. Transformers are only designed for high voltages