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Tuesday, 18 August 2026
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Physics Past Questions and Answers

Topic: (a) Electromagnetic Induction

Jamb Physics Questions - (a) Electromagnetic Induction

Question 66:
A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil. If the input voltage is 100 volts, the output voltage is
  • A 5 volts
  • B 10 volts
  • C 15 volts
  • D 20 volts
View Answer & Explanation
Question 67:
Which expression gives magnetic flux?
  • A QVB sin\(\theta\)
  • B \(\frac{\mu \phi I}{2 \pi r}\)
  • C BA cos \(\theta\)
  • D -N \(\frac{d \phi}{dt}\)
View Answer & Explanation
Question 68:
A magnet relay is a device used for?
  • A Reading the magnitude of magnetic flux
  • B Controlling another circuit carrying larger current
  • C Turning in sports
  • D Storing magnetic field
View Answer & Explanation
Question 69:
A step-down transformer is used on a 2.2 kV line to deliver 110 V. How many turns are on the primary windings if the secondary has 25 turns?
  • A 20
  • B 250
  • C 200
  • D 500
View Answer & Explanation