what is about right handthumb rule for magnetic field???

The right hand rule states that, to find the direction of the magnetic force on a positive moving charge, the thumb of the right hand point in the direction of v, the fingers in the direction of B, and the force (F) is directed perpendicular to the right hand palm

Dear ,According to right hand thumb rule , in a current carrying loop curl figure in the direction of current and thumb will give you the direction of magnetic field.Similarly in a straight current carrying conductor place thumb in the direction of current and the other fingers on curl will give the direction of magnetic field..Hope this will help..