The work function of electrons from silver is 7.85 * 10 ^ -19 J. Determine the wavelength

The work function of electrons from silver is 7.85 * 10 ^ -19 J. Determine the wavelength of the red border of the photoelectric effect for silver.

Avih = 7.85 * 10 ^ -19 J.
h = 6.6 * 10 ^ -34 J * s.
s = 3 * 10 ^ 8 m / s.
λcr -?
Let us write down the condition of the silver photoeffect: Avykh = h * νcr, where h is Planck’s constant, νcr is the frequency of the red border of the photoelectric effect.
Let us express the wavelength through the speed of propagation of electromagnetic radiation: νcr = s / λcr.
Avykh = h * s / λcr.
λcr = h * s / Avykh.
λcr = 6.6 * 10 ^ -34 J * 3 * 10 ^ 8 m / s / 7.85 * 10 ^ -19 J = 2.522 * 10 ^ -7 m.
Answer: the wavelength of the red border of the photoelectric effect for silver λcr = 2.522 * 10 ^ -7 m.