The work function for a metallic surface is 4.0 eV. The longest wavelength of light that can cause photoelectron emission is approximately
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 310 nm
According to photoelectric equation,
Work function, $\phi=hv_0=\frac{hc}{λ}$
$⇒λ=\frac{hc}{\phi}=\frac{4.14×10^{-15}×3×10^8}{4}$
$=310nm$