Sodium metal requires a photon with a minimum energy of 4.41 10-19J to emit electrons. (a)

Question:

Sodium metal requires a photon with a minimum energy of 4.41 × 10-19J to emit electrons.
(a) What is the minimum frequency of light necessary to emit electrons from sodium via the photoelectric effect?
(b) What is the wavelength of this light?
(c) If sodium is irradiated with light of 405 nm, what is the maximum possible kinetic energy of the emitted electrons?
(d) What is the maximum number of electrons that can be freed by a burst of light whose total energy is 1.00 mJ?