Question

Find the longest wavelength of light that can eject an electron from gold. The work function of gold is 5.1 eV (1eV= 1.6x10^-19 joules).

Answer 1

step;1

Given that

work function W=5.1*1.6*10^-19=8.16*10^-19 J

step;2

now we find the longest wavelength

maximum wavelength =hc/w

                                =6.62*10^-34*3*10^8/8.16*10^-19

                                =2.434*10^-7 m