A student sets up a straight conducting wire horizontally over a magnetic compass…
PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
A student sets up a straight conducting wire horizontally over a magnetic compass exactly as Ørsted did. The wire is connected to a key and a battery so that the current can be started or stopped at will.
(i) Describe the arrangement clearly, mentioning the relative positions of the wire, the compass and the direction of current used in the initial observation.
(ii) When the key is pressed, the compass needle deflects. Explain the reason for this deflection.
(iii) The needle returns to its original north–south position when the key is released. Explain why this happens.
(iv) Predict and explain the change in the direction of deflection if the terminals of the battery are interchanged while all other conditions remain the same.