Why is the electrometer needle deflected in both cases?

If the plate introduced into the sphere is positively charged, it attracts free electrons, as a result of which a lack of free electrons forms on the rod and arrow, and both of them acquire a positive charge. If the plate is negatively charged, then it will repel free electrons, as a result of which an excess of free electrons is formed on the arrow and the rod, and they both acquire a negative charge.

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