Question

what is pattern of field lines inside a solenoid ?What do they indicate?

Answer 1

A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called asolenoid. The pattern of the magnetic field lines around a current-carryingsolenoid is illustrated in Fig.1. ... Thisindicates that the magnetic field is the
same at all points inside the solenoid.

hope it helps you

Answer 2

the pattern of field lines inside a solenoid is just like the field lines in a bar magnet that is curves
they indicate that they have magnetic properties due to electric current as a bar magnet