Question

If ultraviolet light of wavelength 200. nm causes electrons to be ejected from a gold surface with a kinetic energy of 1.88 x 10^-19 J, what is the threshold frequency for ejection of an electron from gold? And what is the wavelength of the electrons?

Answer 1

E=hv, v=E/h=1.88*10^-19/6.626*10⁻³⁴=2.8373076*10¹⁴ Hz

λ=c/v=299 792 458/2.8373076*10¹⁴=1.0566*10^-6 m = 1056.6 nm