Is the following hexagons, made up of two different material $P$ and $Q$, current enters and leaves from points $X$ and $Y$ respectively. In which case the magnetic field at its centre is not zero

In a region of space, a uniform magnetic field $B$ exists in the $y$-direction. A proton is fired from the origin, with its initial velocity $v$ making a small angle $\alpha$ with the $y$- direction in the $yz$ plane. In the subsequent motion of the proton

A particle of charge $-q$ and mass $m$ enters a uniform magnetic field $\overrightarrow{B}$ (perpendicular to paper inwards) at $P$ with a velocity $v_0$ at an angle $\alpha$ and leaves the field at $Q$ with velocity $v$ at angle $\beta$ as shown in fig., then

In which regions(s) a neutral point may not exist, that is where the magnetic field is not zero?

The emerging particles at $S_2$, enter a second magnetic field $\overrightarrow{B_2}$, also pointing out of the page. The particle then moves in a semicircle, striking an electronic sensor at a distance $x$ from the entry slit.