The work function of a substance is 4 eV. What is the approximate longest wavelength of light that can cause photo-emission ?
Answer & explanation
Correct answer: option 1
$λ_{th}=\frac{hc}{\phi}=\frac{12400}{4}Å=3100Å=310nm$
$λ≤λ_{th}⇒λ≤310nm$
The work function of a substance is 4 eV. What is the approximate longest wavelength of light that can cause photo-emission ?
Correct answer: option 1
$λ_{th}=\frac{hc}{\phi}=\frac{12400}{4}Å=3100Å=310nm$
$λ≤λ_{th}⇒λ≤310nm$