It takes 4.90 ✕ 10-19 J of energy to remove one electron from a certain metal surface. What is the maximum wavelength of light capable of causing this effect?

Answer 1

Photoelectric Effect

E = hc / λ

E = energy = 4.90x10^-19 J

h = Planks constant = 6.626x10^-34 J-sec

c = speed of light =~ 3x10⁸ m/sec

λ = wavelength (m)

Solving for λ

λ = (6.626x10^-34 J-sec) (3x10⁸ m/sec) / 4.90x10^-19 J

λ = 4.06x10^-7 m = 406 nm