Is a metalloid malleable or brittle

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)

Compare and contrast physical changes with chemical changes.

Which example is a mechanical wave?     a.microwave    b.radio wave    c.water wave    d.ultraviolet light