What is the amount of light that passes through the lens and reaches the digital sensor called?

The amount of light that passes through the lens and reaches the digital sensor is called exposure.
So, exposure determines how much light or darkness will get to the sensor, and thus how light or dark the image will be when you take a photo. There are settings that are responsible for this: ISO, aperture, and shutter speed - which together are called "the exposure triangle."

These traits are all equally important in recognizing the validity of artwork mainly due to an artists' consistent style and reputation which they have developed over a lengthy period of time. most famous paintings contain specific characteristics of the artist who created it. an appraiser would pay close attention to certain key elements within the painting, as well as an accuracy in measurement and color shade. blended textures and outlines are essential in recognizing an authentic piece from a copy. signature and imagery exist in epic proportions to balance out each trait as they coexist in harmony, depending on preference and style of each artist. no two original pieces are virtually identical, although it may be almost impossible to see discrepancy with the naked eye.