CBSE Class 10 Science 2019 · Paper 31/4/3 · Question 8

Right-hand thumb rule: Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points in the direction of the current. Then the direction in which your fingers wrap around the conductor gives the direction of the magnetic field lines around it. Applying it to the loop (current clockwise as seen from above): gripping each part of the loop with the thumb along the current, the fingers go down into the table on the side facing the centre and come up on the outer side. So: Inside the loop: the magnetic field is perpendicular to the plane of the table and directed into it (downwards). Outside the loop: the magnetic field is perpendicular to the plane of the table and directed out of it (upwards).