Me pueden ayudar con estos ejercicios por favor y gracias

Which phrase best describes the rock's texture? 1.jagged grains 2.coarse grains 3.rounded grains 4.non-banded grains

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)

If 10.g of agno3 is available, what volume of 0.25 m agno3 can be prepared