CBSE Class 12-science Answered
A horizontal overhead power line carries a current of 120 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 4.5 m south of the line?
Since the current and the distance is given in the question,
That is I = 20 A, r = 4.5 m
Using the right hand thumb rule, i.e. thumb in the direction of current, and fingers curl in the direction of magnetic field. It is clear that the magnetic field at the observation point is directed towards the reader.