(a) What is a solenoid? Draw a sketch of the pattern of field lines of the magnetic field through and around a current carrying solenoid. (b) Consider a circular loop of a wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right hand rule to find out the direction of the magnetic field inside and outside the loop.



A long cylindrical coil of insulated copper wire of large number of circular turns is called Solenoid.When a current is passed through a solenoid,it produced  magnetic field around it. Its magnetic field pattern is shown in the image.
When a current is passed through a solenoid, the current in each circular loop has the same direction, their magnetic effects get added up producing a strong magnetic field. Inside the solenoid, the magnetic fields is almost uniform and parallel to the axis of the solenoid.