Final answer:
The charge of the metal dome when the machine is switched on cannot be determined with the given information.
Step-by-step explanation:
When the machine is switched on, the charge of the metal dome cannot be determined with the given information. The options provided (positively charged, negatively charged, neutral) are all possibilities depending on the specific conditions and actions of the machine. Depending on how the machine is designed and how it functions, it could result in the dome becoming positively charged, negatively charged, or remaining neutral.