a. Describe the importance of the Planck constant h in describing the behaviour of electromagnetic radiation and of electrons.
b. Light of wavelength 550 nm is incident normally on a metal plate. The intensity of the light is 800 W m⁻². All the incident light is absorbed by the metal plate. The plate has dimensions 5.0 cm × 5.0 cm.
i. Explain how the light hitting the plate exerts force on the plate.
ii. Calculate the momentum of each photon of light.
iii. Calculate the force exerted on the plate due to the light.