Question

You are making photoelectric measurements on an electrode of an unknown metal. With zero potential difference applied by the battery, you shine various freqencies of light on the cathode. You detect a small photocurrent for light with wavelength up to 451 nm. What metal is the electrode made of and why?

Copper

Aluminum

Gold

Iron

Potassium

b. You change out the electrode, and now the longest wavelength is in the ultraviolet at 290 nm. What is the metal?

Copper

Aluminum

Gold

Iron

Potassium

Sodium

Tungsten

Sodium

Tungsten

Answer 1

We get for light coith coare lenph photo curent 3 mall o 451 nm worh Suncdhon of the medal ie, at this .langtA oave just light=(E) energy od 45 nm 1 ev Now as oosk uncdion cev) mefal 4.7 CoPpe 4.08 Aluminum Gald 5.1 Ion 4.5 2.3 Potassium work anction of potaseium only accao ding to List lecdrode made of Potassium thus the Over come.

Νοω change of electoode, the longest wavelangts 290nm Light is Energy responding to 290 nm Cooo hc E = 4.26 er. is the longes Heve length 290nm Coave f the the coork funcdion Thues coovelengts to 4 26 eV. must metal neader the elecdovde i3-Aluminum data Accooding to 4.07 e v Aluminum of coosk Sun ion as