The Work Function of a Particular Metal Is $4.20 \times 10 ^{- 19} \mathrm {~J}$

Multiple Choice

The work function of a particular metal is $4.20 \times 10 ^{- 19} \mathrm {~J}$ What is the photoelectric cutoff (threshold) wavelength for this metal? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)

A) 473 nm
B) 308 nm
C) 393 nm
D) 554 nm