When a Metal Is Illuminated by Light, Photoelectrons Are Observed $520 \mathrm {~nm}$

Multiple Choice

When a metal is illuminated by light, photoelectrons are observed provided that the wavelength of the light is less than $520 \mathrm {~nm}$ . What is the metal's work function? ( $c = 3.00 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , h = 6.626 \times$ $10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s } , 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J}$ )

A) $2.6 \mathrm { eV }$
B) $2.8 \mathrm { eV }$
C) $3.0 \mathrm { eV }$
D) $2.4 \mathrm { eV }$