A fixed potential difference is maintained across two horizontal metal plates. An electrically charged oil droplet is balanced and remains still in the electric field between the plates. When part of the oil evaporates, the droplet’s mass decreases and it begins to accelerate. Its charge stays unchanged. In what direction will the droplet accelerate, and what alteration must be made to the plate spacing to prevent this acceleration?
- Adownwards, decrease
- Bdownwards, increase
- Cupwards, decrease
- Dupwards, increase