Magnetic effect of a current

1. What is the shape of magnetic field lines around a wire with electric current?

2. What is the relationship between the strength of magnetic field and the distance from the wire.

3.  What is the relationship between the strength of a magnetic field and the current in the wire.

4. What is right-hand grip rule for the straight wire?

5. What is solenoid?

6. What is the shape of the field in the solenoid?