Answer asap !

a solenoid field is:

1. never zero
2. located outside the coil only
3. increased with an increased current flow
4. entirely the coil

A solenoid field is increased with the increase in the current flow through the coil.

Explanation:

A solenoid is a current carrying coil with a significant number of loops. It works like an electromagnet inside which, a uniform and strong magnetic field is created. The magnetic field outside the solenoid field is nearly zero but not exactly zero.

While experimenting with the solenoid, scientists came to know that the magnetic field generated by the solenoid increases with the increase in the current, flowing through the solenoid.

The magnetic field works strongly around the arena of coil. The field changes its direction only near the ends and gets weak. Else its uniform throughout the loops.

The magnetic field inside the solenoid can be formulated as,

Where,

B = Magnetic field generated by the solenoid

= Constant

I = Current flowing through the loops of the solenoid

a and b sometimes have a positive value