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Sunday, 21 June 2026
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Physics Past Questions and Answers

Topic: Electromagnetic Induction

Jamb Physics Questions - Electromagnetic Induction

Question 21:
The iron core of an induction coil is made from bundles of wire so as to
  • A Minimize eddy-currents
  • B Generate eddy-current
  • C Prevent sparking at the contact breaker
  • D Get the greatest posible secondary voltage
View Answer & Explanation
Question 22:
A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.
  • A 0.625A
  • B 1.600A
  • C 2.500A
  • D 6.250A
View Answer & Explanation
Question 23:
A semiconductor diode is used in rectifying alternating current into direct current mainly because it
  • A Allows current to flow in either direction
  • B Is non-linear
  • C Offers a high input resistance
  • D Allows current to flow only in one direction
View Answer & Explanation
Question 24:
A conductor of length 2m carries a current of 0.8A while kept in a magnetic field of magnetic flux density 0.5T. The maximum force acting on it is
  • A 0.2N
  • B 0.8N
  • C 3.2N
  • D 8.0N
View Answer & Explanation
Question 25:
The primary coil of a transformer has N turns and is connected to a 120 V a.c. power line. If the secondary coils has 1 000 turns and a terminal voltage of 1 200 volts, what is the value of N?
  • A 120
  • B 100
  • C 1 000
  • D 1 200
View Answer & Explanation