Which of the following statements regarding photoemission of electrons is correct?

Photoelectric emission is instantaneous with the incidence of light.

• Kinetic energy of electrons increases with frequency. Increase in intensity causes more number of electrons to be ejected.
• Electrons are emitted when the wavelength of the incident electrons is below a certain threshold wavelength.
• Photoelectrons are emitted whenever gas is irradiated with light of appropriate frequency.