Final answer:
When a positive charge is brought close to a neutral conductor with a cavity, the inside surface of the cavity becomes negatively charged, while the outside surface becomes positively charged.
Step-by-step explanation:
When a positive charge is brought close to a fixed neutral conductor that has a cavity, the charge separation takes place in the conductor. The inside surface of the cavity becomes negatively charged, while the outside surface becomes positively charged. Therefore, the cavity is not neutral, it has a net negative charge on its inside surface.