Light of wavelength 400 nm is incident on a certain metal. The stopping potential for the emitted electrons is measured to be 1.2 V. What is the work function of this metal? (Planck's constant h = 6.626x10⁻³⁴ J.s=4.136x10⁻¹⁵ eV-s.)
a. 4.3 eV
b. 3.1 eV
c. 1.9 eV
d. 1.2 eV
e. 0.95 eV
