Question

The work function of a substance is `4.0 eV`. The longest wavelength of light that can cause photo electron emission from this substance is approximately. (a) `540 nm` (b ) `400nm` (c ) `310 nm` (d) `220 nm`
A. 540 nm
B. 400 nm
C. 310 nm
D. 220 nm

Answer 1

Correct Answer - C
`lamda_(min)=(hc)/(omega)=(6.63xx10^(-34)xx3xx10^(8))/(4(1.6xx10^(-19)))=310xx10^(-9)`