What determines the intensity of light in the photon picture of light?

What is a ray of light?

(Attempt any nine of the following questions) What are coherent sources? In a Young's double slit experiment the intensity of light at a point on the screen where path difference lambda is K units. Find the intensity at a point where the path difference is lambda/ 3 .

What is a beam of light?

What is the dimensional formula of light year ?

Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m/s .

Who demonstrated the interference of light first?