2454

Physics Modern Physics Level: High School

Photoelectric Effect

Radiation with a wavelength of 238 nm shines on a metal surface and ejects electrons that have a maximum speed of 3.75 x 10^5 m/ s . Which one of the following metals is it , the values in parentheses being the work functions : potassium (2.24 eV) , calcium (2.71 eV) , uranium (3.63 eV), aluminum(4.08 eV) , or gold (4.82 eV) .