Answer to Question #117424 in Physics for James

Question

(For Waves, Optics and Modern Physics)
Ultraviolet light with a wavelength of 90.0 nm shines on a gas of hydrogen atoms in their ground states. Some of the atoms are ionized by the light. What is the kinetic energy of the electrons that are freed in this process? (in eV)
Kmax= hf- Eo
Kmax = 6.626*10^-34 *3.0*10^8 / (90.0*10^-9) - 13.606*1.602 *10^-19 = 2.899 *10^-20 J=0.181 eV
(using 4.136*10^-15 eV*s gives the same answer)
The real answer is supposed to be 0.213 eV, what did I do wrong?

Answer 1

$$K=\frac{hc}{\lambda}-E_0$$

$$K=\frac{1239.841984}{90}-13.606=0.170\ eV$$