From the surface of a round wire of radius a carrying a direct current i, a positive charge q escapes with a velocity `v_0` perpendicular to the surface. Find what the maximum distance of the electron will be from the axis of the wire before it turns back due to the action of the magnetic field generated by the current.

Explanation

To solve the problem of finding the maximum distance \( X \) of a positive charge \( q \) escaping from a round wire of radius \( a \) carrying a direct current \( I \), we can follow these steps:

### Step 1: Understand the Situation
We have a round wire with radius \( a \) carrying a current \( I \). A positive charge \( q \) escapes from the surface of the wire with an initial velocity \( v_0 \) perpendicular to the surface. The current in the wire generates a magnetic field around it.

### Step 2: Determine the Direction of the Magnetic Field
Using the right-hand rule, we can determine the direction of the magnetic field \( B \) around the wire. For a straight wire carrying current \( I \) in the positive z-direction, the magnetic field at a distance \( x \) from the wire is given by:
\[
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