At the two ends of a long straight solenoid, N- pole and S- pole are formed for a current. The wrong statement among the following is 

Solenoid: An electromagnet that creates a regulated magnetic field by winding a coil into a closely packed helix.

When an electric current is sent through it, it produces a homogeneous magnetic field.

A solenoid's magnetic field is proportional to the supplied current and the number of turns per unit length.

The magnetic field within a solenoid is not affected by its diameter.

Inside, the field remains constant.

As illustrated in the image, the pattern of field lines generated by the solenoid mimics that of a current-carrying conductor.