Physics (AS & A Level) · Oct / Nov 2018 · Paper 11 · Question 2

When a beam of light is incident on a surface, it delivers energy to the surface. The intensity of the beam is defined as the energy delivered per unit area per unit time. What is the unit of intensity, expressed in SI base units?

1. Akg m⁻² s⁻¹
2. Bkg m² s⁻³
3. Ckg s⁻²
4. Dkg s⁻³

As printed in the paper