What is an atomic element of carbon

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)

Identify the electromagnets with poles that are reversed from the electromagnet shown above

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?