What is difference in the pattern of magnetic field due to a circular loop and inside a solenoid?

What is the nature of magnetic field inside a solenid?

A circular loop carrying a current is placed on a horizontal surface (current is in the clockwise direction). What is the direction of its magnetic field at the centre? What is the direction of the magnetic field at a point outside the surface of the loop?

What is the principle of an electromagnet?

When is the force on a current carrying wire

(i) maximum

(ii) minimum