Two magnetic field lines can never intersect each other because
- A.the field would then be zero at that point
- B.there would be two directions of the field at the same point, which is impossible
- C.the lines are imaginary
- D.the magnetic poles always exist in pairs
Correct answer
Explanation
The correct answer is B. The tangent drawn to a magnetic field line at any point gives the direction of the field at that point. If two lines crossed, two different tangents could be drawn at the point of crossing, which would mean the compass needle placed there would have to point in two directions at once. Since that is impossible, field lines never intersect.
Option A is wrong because the field being zero is a different situation, called a neutral point, where no line passes at all rather than two crossing. Option C is beside the point: field lines are indeed a way of picturing the field, but even as a picture they must show one direction at each point, so being imaginary is not the reason. Option D states a true fact, that a magnet always has both poles and a single pole cannot exist, but it explains why lines are closed curves and not why they cannot cross.
Read the full article: Electricity and Magnetism: Laws, Rules and PYQs
Practice Questions
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