Problem database

One electrode of a flat capacitor is an emitter of electrons, the other consists of parallel wires, the gaps between which are significantly smaller than the distance $d$ between the electrodes. Potential difference between the electrodes $V$. Determine the spread of electrons passing through the second electrode by the "transverse" energy, if the gap between the wires is $a$, and their thickness is $b$. Ignore the initial electron velocity.