Draw the pattern of magnetic field lines produced around a current carrying straight conductor passing perpendicularly through a horizontal cardboard. State and apply right-hand thumb rule to mark the direction of the field lines. How eill the strength of the magnetic field change when the point where magnetic field is to be determined is moved away from the straight conductor ? Give reason to justify your answer.

Explanation

Statement of right hand thumb rule.
The magnetic field strength decreases with increase of distance from the current carrying conductor.
Reason : There is inverse relation between field strength and distance from current carrying conductor .
Note : Direction of magnetic field should be in accordance with direction of current.