The Threshold Wavelength for Photoelectric Emission of a Particular Substance

Multiple Choice

The threshold wavelength for photoelectric emission of a particular substance is 500 nm.What is the work function (in eV) ?

A) 4.2
B) 4.0 *10 ^{- 19}
C) 4.0 *10 ^{- 10}
D) 2.5 *10 ^{- 19}
E) 2.5