[OBJ/EM-04004] Plane conductor and a point charge

A charged particle is at a distance \( d\) from an infinite conducting plane maintained at zero potential. When released from rest, the particle reaches a speed \( u\) at a distance \( d/2\) from the plane. At what distance from the plane will the particle reach the speed \( 2u\)?

1. \( d/6 \)
2. \( d/3 \) \\
3. \( d/4 \)
4. \( d/5 \)