Question

with magnetic field lines how can you find the direction and strength of magnetic field​

Answer 1

The properties of magnetic field lines can be summarized by these rules: The direction of the magnetic field is tangent to the field line at any point in space. A small compass will point in the direction of the field line. The strength of the field is proportional to the closeness of the lines.

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Answer 2

The direction of magnetic field at a place can be determined by using a compass needle. A compass needle need place near a magnet gets deflected due to the magnetic force exerted by the magnet. The north an the needle of the compass indicates the direction of magnetic field at the point where it is placed.