Quick questions on Charged particles in uniform fields: WACE Year 12 Physics Unit 3

Two oppositely charged parallel plates a distance $d$ apart with potential difference $V$ produce a uniform field of strength

When a charge moves through a potential difference $V$, the work done on it is $W=qV$, which becomes kinetic energy if it starts from rest:

Deflection questions are the most common application, so it pays to have a fixed method. First find the field $E=V/d$ and hence the perpendicular acceleration $a=qE/m$. Treat the motion in two independent directions: along the plates the velocity is constant, so the time spent between the plates is $t=L/v_x$ where $L$ is the plate length. Across the plates the particle starts with zero perpendicular velocity and accelerates, so the sideways deflection while still inside the field is $y=\tfrac{1}{2}at^2$.