Observing the photoelectric effect

I am slightly confused by the explanations given as bullet points (see picture).

Surely, if the electroscope is charged negatively, when the UV radiation hits the zinc surface, the leaf should attract the surface, since the surface is positively charged (as electrons have been 'given off'). Yet, the book says it falls - I don't understand why...

Same with when the electroscope is positively charged - the leaf should fall, as it should repel the surface, when it loses electrons. But the book states the opposite :/

What am I misreading here?




Posted from TSR Mobile

When the zinc surface is negatively charged, the metal stem of the electroscope also becomes negatively charged. The charge also spreads to the gold leaf. This means that the stem and the leaf have the same charge, so the leaf rises away from the stem.

Ah thank you, I get it


Posted from TSR Mobile