Question

Light intensity is?

The distance between successive crests of a wave?

The interference pattern that shows light is a wave?

The rate at which a waves energy flows through a given unit of area?

The direction that photons travel?

Answer 1

The rate at which a waves energy flows through a given unit of area

Answer 2

The correct answer is:
The rate at which a waves energy flows through a given unit of area

In fact, light intensity is defined as the light power per unit of area:

`I= (P)/(A)`
but the power is the energy carried by the light per unit of time:

`P= (E)/(t)`
this means that the intensity can be rewritten as

`I= (E)/(tA)`
So, it's basically the rate of energy (per unit of time) through a given surface.