Pennies are made of zinc coated with copper. copper has a work function of 4.7 ev. the ozone layer blocks nearly all solar radiation with wavelength shorter than 320nm, but a very small amount of 200 nm light still manages to reach the earth's surface. can direct sunlight produce photoelectrons from a penny?

yes  it can  λ =265  nm

Explanation:

Here we will use  the relationship

   E = h c/λ  ∴   λ  = E/ hc  where

                                          h= Plank's constant

                                           c= Speed of light

                                           λ = Wavelength = ?

Substituting

note need E in J ,

E = 4.7 eV x 1.602 x 10⁻¹⁹ J/eV = 7.5 x 10⁻¹⁹ J)

λ = 7.5 x 10 ⁻¹⁹ J / (  6.626 x 10⁻³⁴ Js x 3 x 10^8) =  2.65 x 10⁻⁷ m = 2.65

=  2.65 x 10⁻⁷ m x 1 x 10⁹ nm/m = 265 nm

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.