State Right-Hand Thumb Rule to find the direction of magnetic field around a straight conductor carrying current. How will this magnetic field be affected on:
(a) increasing the current through the conductor,
(b) changing the direction of flow of current through the conductor?

Explanation

Hold the straight conductor in your right hand such that the thumb points out in the direction of flow of current. The direction of curling of the fingers gives the direction of the magnetic field lines around the conductor.
(a) increasing current through the conductor increases the strength of the magnetic field.
(b) changing the direction of flow of current through the conductor changes the direction of the magnetic field. However, the strength of the magnetic field remains the same.