H Exp – Radiation and Matter 08 – The photoelectric effect

Aim – To compare the effect of white light and u.v. radiation on charged electroscopes.

Instructions

The electroscope can be charged positively or negatively using acetate or polythene rods.

▪ Without the zinc plate in place, charge the electroscope with a positive charge. Shine white light, then ultra violet light on the top plate of the electroscope and observe the effect, if any.
▪ Repeat this for a negative charge on the electroscope.
▪ Add the zinc plate (which has been rubbed to remove any oxide layer). Observe the effect, if any, when white light and then ultra violet light is shone on the plate.