JAMB - Physics (2018 - No. 29)
A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed, the result is that Y has
no charge and a zero potential
a positive charge and a zero potential
a negative charge and a positive potential
a negative charge and a negative potential
설명
When a positively charged rod X is brought near an uncharged metal sphere Y, it induces a separation of charges. The side of the sphere near the rod becomes negatively charged as electrons are attracted to it, while the far side becomes positively charged.
When the finger touches the sphere, electrons can flow from the finger into the sphere, giving it an excess of electrons. After removing the finger and the rod, the sphere retains a negative charge.