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JAMB Physics 1983 Question 40

Question 40

Magnetism

In Fig. 7 above, QR is a vertical conductor and the current I flows from R to Q. P is a point on the horizontal plane and is to the South of the wire. The direction of the magnetic field at P due to the current is

Diagram for this question
  1. A.upward
  2. B.north
  3. C.south
  4. D.west
  5. E.east
Show the answer and explanation

Answer: E (east)

Explanation

The current flows upwards. By the right-hand grip rule the field lines circle anticlockwise when seen from above, so at a point due south of the wire the field points east.