Wich group was the control group? The experimental group?

Asample of silver (with work function ? = 4.52 ev) is exposed to an ultraviolet light source (? = 200 nm), which results in the ejection of photoelectrons. what changes will be observed if: silver is replaced with copper (? = 5.10 ev) more photoelectrons ejected no photoelectrons are emitted fewer photoelectrons ejected more energetic photoelectrons (on average) less energetic photoelectrons (on average)

Si una estrella no tiene paralaje medible, ¿qué puedes inferir?

Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li