If plane-polarised light with amplitude $A$ is incident on a polarising filter, as illustrated, the amplitude of the transmitted light is $A \cos \theta$. The intensity of the original beam is $I$. Determine the intensity of the transmitted light when $\theta$ is $60.0^\circ$?
- A$0.250\,I$
- B$0.500\,I$
- C$0.750\,I$
- D$0.866\,I$