Question

Light intensity is?

Answer 1

Answer:

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:
$I= \frac{P}{A}$
but the power is the energy carried by the light per unit of time:
$P= \frac{E}{t}$
this means that the intensity can be rewritten as
$I= \frac{E}{tA}$
So, it's basically the rate of energy (per unit of time) through a given surface.