Question

Calculate the kinetic energy of the electrons when radiation of wavelength of 1.50 × 102 nm falls on a metal. The threshold wavelength of the metal is 2.00 4494_files/i0110000.jpg 102 nm. a. 6.20 eV c. 2.07 eV b. 8.26 eV d. 14.4 eV

Answer 1

The kinetic energy of a photon can be calculated from the product of the planck's constant and the frequency of the light. In this problem, we are given the wavelength. Frequency and wavelength are related. We do as follows:

E = hv where h is the Plank's constant and v is the frequency (v = speed of light / wavelength )

E = h (speed of light / wavelength)
E = 6.63x10^-34 ( 3x10^8 )/ (1.50x10^-7 )
E = 1.326x10^-18 J = 8.26 eV