Question

The work function of a material is the minimum energy required to emit an electron from the material. The work function of Ag is 7.59 x 10^ -19 J

a) If I'm in Australia (where a lot more UV light makes it through the depleted ozone layer ...) and I'm wearing silver earrings when the sun comes out irradaiting me with light that has a wavelength of 185 nm, will electrons be emitted from the earrings?

b) If radiation hits me that has more energy than required to emit an electron, what happens to the additional energy?

Answer 1

((A) Energy of radiaion is given as

E = hv,

h = planks constant = 6.62 X 10^-34

v = frequency of radiation =c / λ , c = velocity of light = 3.0 X 10⁸m/s and λ = wavelength = 185nm = 185 X 10^-9

E = 6.62 X 10^-34 X 3.0 X 10⁸ / 185 X 10^-9 = 0.1073 X 10^-19 = 1.07 X 10^-20 J

Since the energy of radiation is less than work function hence electrons can not be ejected by light from the ear ring.

(B) The additional energy will be imparted to electron as kinetic energy.