Q.1
What is induced across the ends of an electrical conductor which moves through a magnetic field?
  • A potential difference
  • A resistance
  • A current
  • A capacitance
Q.2
What can be used to induce a potential difference at the ends of a coil of wire?
  • Heat
  • A vacuum
  • Magnet
  • Bread
Q.3
Considering the basic structure of a transformer, what does an alternating current in a primary coil produce in the iron core which it surrounds?
  • A static magnetic field
  • A changing magnetic field
  • A static electric field
  • A changing electric field
Q.4
In a step-up transformer, is the potential difference created in the secondary coil more, less or equal to the potential difference in the primary coil?
  • More
  • Less
  • Equal
  • Values for the coils are required to calculate this
Q.5
In a step-down transformer, is the potential difference created in the secondary coil more, less or equal to the potential difference in the primary coil?
  • More
  • Less
  • Equal
  • Values for the coils are required to calculate this
Q.6
Which equation correctly relates the potential difference across the primary and secondary coils of a transformer?
  • Vp⁄Vs = np⁄ns
  • Vp⁄Vs = ns⁄np
  • Vs⁄Vp = np⁄ns
  • Vp⁄Vp = np⁄ns
Q.7
Which types of transformers operate at high frequency?
  • Laminated core
  • Variac
  • Stray field
  • Switch mode transformers
Q.8
What is an advantage of using switch mode transformers over a traditional transformer when working from a 50 Hz mains supply?
  • They change the electricity at a quicker rate
  • They are lighter and smaller
  • They are more robust
  • They are more efficient
Q.9
What is another advantage of using switch mode transformers when no load is applied?
  • They use little power
  • They use lots of power
  • They store electricity
  • There is no advantage offered by switch mode transformers when no load is applied
Q.10
A primary coil within a transformer has 48 turns around its coil and has a potential difference applied to it of 12 V. If the secondary coil has 60 turns around its coil, what is the potential difference produced at the ends of the secondary coil?
  • 12 V
  • 14 V
  • 15 V
  • 9.6 V
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